Xcode Previews

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Create an app UI and configure almost everything your users see using Xcode Previews.

Posts under Xcode Previews tag

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Unable to create SwiftUI previews in Xcode 26 for iOS 15.5
I am getting this error msg when I try to run a SwiftUI Preview on an iOS 15.5 simulator: Termination Reason: Namespace DYLD, Code 1, Library missing | Library not loaded: /usr/lib/swift/libswift_StringProcessing.dylib | Referenced from: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator/libLiveExecutionResultsLogger.dylib | Reason: tried: '/Users/hfg/Library/Developer/Xcode/DerivedData/Testios15sim-aawlbfbtggzozseoekycwwpadhrc/Build/Intermediates.noindex/Previews/iphonesimulator/Testios15sim/Products/Debug-iphonesimulator/libswift_StringProcessing.dylib' (no such file), '/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 15.5.simruntime/Contents/Resources/RuntimeRoot/usr/lib/swift/libswift_StringProcessing.dylib' (no such file), '/usr/lib/swift/libswift_StringProcessing.dylib' (no such file), '/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 15.5.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libswift_StringProcessing.dylib' (no such file) FYI I tried with the Legacy Preview Execution both on and off
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497
Nov ’25
Cannot Preview in this file. Simulator was shutdown during an update.
Hello, I am facing a recurring issue with Xcode iOS simulator (preview). I want to preview a SwiftUI for iOS in Xcode, but the Simulator app fails to boot up. I receive the follow error in Xcode: Cannot Preview in this file. Simulator was shutdown during an update. I have tried the following: Uninstall Xcode and reinstall it again Deleting all developer data Deleting Xcode cache Reinstalling iOS Simulator runtimes and reconfiguration of simulators. Tested using different simulator and runtime versions. "xcrun simctl --set previews delete al" I reported the issue: FB20485454 FB20987522 Thank you. Best regards, Jens
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412
Nov ’25
Missing Context menu items in Xcode 26 on a fresh project
When following the official SwiftUI Tutorial "Landmarks", I should be able to Cmd-Ctrl-Click an element of a preview in Selectable mode to view a list of options. But Xcode shows only one option (Embed). Furthermore, if I try to type anything the popover breaks completely and grows in length infinitely. I am not sure whether this is a bug, or I missed something when installing Xcode, or both
2
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664
Nov ’25
iOS Simulator in Xcode 26.1 makes ReportCrash process run at 60-160% of CPU
My MBP M1 Pro gets really hot. iOS 26.1 Simulator in Xcode 26.1 makes ReportCrash process run at 60-160% of CPU shows Activity Monitor. MacOS 26.1. I've reported this via Feedback Assistant: FB20918609. Is there a way to quit this process permanently? When I Force Quit this it opens again immediately. Only way to stop it is to quit Simulator. But then again, I need to use the Simulator.
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1.5k
Nov ’25
Build Issue
I am trying to make build for my project followed all step and all but Igot Showing Recent Errors Only Build target PCS_EmpApp of project PCS_EmpApp with configuration Debug ProcessInfoPlistFile /Users/mayankjain/Library/Developer/Xcode/DerivedData/PCS_EmpApp-bhccfqkphneiyabcysmesvskjrrm/Build/Products/Debug-iphonesimulator/PCS_EmpApp.app/Info.plist /Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync/Info.plist (in target 'PCS_EmpApp' from project 'PCS_EmpApp') cd /Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync builtin-infoPlistUtility /Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync/Info.plist -producttype com.apple.product-type.application -genpkginfo /Users/mayankjain/Library/Developer/Xcode/DerivedData/PCS_EmpApp-bhccfqkphneiyabcysmesvskjrrm/Build/Products/Debug-iphonesimulator/PCS_EmpApp.app/PkgInfo -expandbuildsettings -format binary -platform iphonesimulator -o /Users/mayankjain/Library/Developer/Xcode/DerivedData/PCS_EmpApp-bhccfqkphneiyabcysmesvskjrrm/Build/Products/Debug-iphonesimulator/PCS_EmpApp.app/Info.plist error: Build input file cannot be found: '/Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync/Info.plist'. Did you forget to declare this file as an output of a script phase or custom build rule which produces it? (in target 'PCS_EmpApp' from project 'PCS_EmpApp') Build input file cannot be found: '/Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync/Info.plist'. Did you forget to declare this file as an output of a script phase or custom build rule which produces it? error . I tried but unable to solve it .
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310
Nov ’25
XCPreviewAgent crashes with KERN_PROTECTION_FAILURE on macOS 26.0.1 Tahoe
Hello, I'm experiencing consistent crashes of XCPreviewAgent when using Xcode Previews on macOS 26.0.1 Tahoe (25A362). Configuration: macOS: 26.0.1 (25A362) - stable release Xcode: 16.0 (23.0.54) - stable release Hardware: MacBook Pro M4 Project: SwiftUI iOS app Issue: Every time I try to use Xcode Previews, XCPreviewAgent crashes with: Exception Type: EXC_BAD_ACCESS (SIGBUS) Exception Subtype: KERN_PROTECTION_FAILURE at 0x0000000340e54000 Termination Reason: Namespace SIGNAL, Code 10, Bus error: 10 The crash occurs in shared memory region during dynamic library loading. What I've tried: Cleared all caches: rm -rf ~/Library/Developer/Xcode/DerivedData Deleted Preview data: rm -rf ~/Library/Developer/Xcode/UserData/Previews Reset simulators: xcrun simctl --set previews delete all Switched xcode-select to /Applications/Xcode.app/Contents/Developer Tried both Xcode stable and Xcode beta Created fresh simulators Clean build (Cmd+Shift+K) Rebooted Mac multiple times The app runs fine on simulator (Cmd+R), but Previews consistently crash.
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286
Oct ’25
Simulator causing Mac audio distortion
I am experiencing an issue where my Mac's speakers will crackle and pop when running an app on the Simulator or even when previewing SwiftUI with Live Preview. I am using a 16" MacBook Pro (i9) and I'm running Xcode 12.2 on Big Sur (11.0.1). Killing coreaudiod temporarily fixes the problem however this is not much of a solution. Is anyone else having this problem?
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13k
Oct ’25
SwiftUI macOS Preview Crash When Using Custom Row Directly Inside List
I’ve hit a strange SwiftUI preview crash that happens on macOS previews when using a view inside a List’s ForEach, resulting in the error Fatal Error in TableViewListCore_Mac2.swift. Only crashes macOS preview - iPhone/iPad preview doesn't crash. Doesn't crash when actually running the app. Here’s a minimal reproducible example, causing the preview to crash. XCode: Version 26.0.1 (17A400) MacOS: 26.0.1 (25A362) import SwiftUI struct Item: Identifiable { let id = UUID() let name: String } struct ItemRow: View { let item: Item var body: some View { HStack { Button(action: {}) { Image(systemName: "play") } Text(item.name) Spacer() ProgressView() } } } struct ContentView: View { @State private var items = [ Item(name: "Item A"), Item(name: "Item B"), ] var body: some View { List { ForEach(items) { item in ItemRow(item: item) } } } } #Preview("Content view") { ContentView() } #Preview("Item row") { ItemRow(item: Item(name: "Item A")) } If I wrap the row in a container, like this: ForEach(items) { item in ZStack { ItemRow(item: item) } } the crash seems to disappear. Has anyone else seen this behavior? What might I be doing wrong? Any ideas about what could be causing this?
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403
Oct ’25
SwiftUI #Previews: How to populate with data
Suppose you have a view: struct Library: View { @State var books = [] var body: some View { VStack { ... Button("add Book") { .... } } } Such that Library view holds a Book array that gets populated internally via a button that opens a modal – or something alike. How can I use #Peviews to preview Library with a pre-populated collection? Suppose I have a static books – dummy – array in my code just for that; still, what's the best way to use that to preview the Library view?
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371
Sep ’25
Xcode Simulator Can't Boot
I am facing a recurring issue with Xcode iOS simulator. I want to preview a SwiftUI for iOS in Xcode, but the Simulator app fails to boot up. I receive the follow error in Xcode: Cannot Preview in this file. Simulator was shutdown during an update. I have tried the following: Deleting Xcode cache Reinstalling iOS Simulator runtimes Completely uninstalling Xcode and deleting all developer data, then reinstalling None of the above steps fix the problem. The only fix I have found is to completely reinstall MacOS 15.4.1. THIS IS TERRIBLE! I have already reinstalled MacOS 15.4.1 once to fix the issue, and I don't want to do it again. If there is another solution, please help me find it! Thank you!!
15
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761
Aug ’25
XCPreviewAgent crashed with some SwiftUI View
The steps to reproduce this issue are a bit complicated. In my app, previewing View A in Package P works fine, but another view in the same package fails to preview. The error message is shown below. It seems that the memory used for the preview is interfering with the shared memory area. This is reported as FB18519266 Exception Subtype: KERN_PROTECTION_FAILURE at 0x00000003402d8900 Exception Codes: 0x0000000000000002, 0x00000003402d8900 VM Region Info: 0x3402d8900 is in 0x3402c8000-0x340a18000; bytes after start: 67840 bytes before end: 7599871 REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL mapped file 3401dc000-3402c8000 [ 944K] r-x/rwx SM=COW Object_id=57e4ac ---> shared memory 3402c8000-340a18000 [ 7488K] rw-/rw- SM=SHM mapped file 340a18000-340f38000 [ 5248K] r-x/rwx SM=COW Object_id=1dc9a049 Termination Reason: ****** 10 Bus error: 10 Terminating Process: exc handler [94787]
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312
Aug ’25
Xcode restarts my Macbook when previewing canvas
I have an issue with Xcode that it crashes my Macbook and restarts it instantly when I unpause the preview canvas. I managed to make it run for a minute longer by not watching a youtube video. I am writing a very simple SwiftUI project for iOS nothing too big to warrant any issues. Does anyone have a solution to fix this? Macbook Pro M3 16GB RAM, 500GB SSD (plenty of storage space) Tahoe 26.0
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261
Aug ’25
Xcode forces my Macbook to restart when previewing canvas
I can't use Xcode without it crashing. Just writing a very simple iOS app with SwiftUI (using only forms and sections). Whenever my canvas updates to correspond to my changes it forces my Macbook to restart. Does anyone have a solution for this. I'll be honest it's becoming really frustrating. Thank you. Macbook M3 Pro 16GB ram, 500gb Space (400gb free space)
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228
Aug ’25
Using Previews causes a system crash on Xcode 26 Beta 4 and MacOS 26 Beta 4
Hey, I've updated to both Xcode 26 Beta 4 and MacOS 26 Beta 4. Both run super stable so far. However, every time I use Xcode Previews for a few minutes, the entire system freezes for a few seconds and then crashes and reboots. I'm trying to generate a system diagnosis (which it offers me after the reboot), but it seems to be stuck generating. It's hard to say what exactly causes the crash, unfortunately. But it happened multiple times after starting to use Xcode Previews. Anyone else has that problem? I've also filed a feedback for this: FB19013059 Cheers Dennis
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Aug ’25
Previews globally fail with CouldNotLoadInputObjectFile error
Whenever I try to use SwiftUI previews, the preview fails with a CouldNotLoadInputObjectFile error like this: == PREVIEW UPDATE ERROR: FailedToLaunchAppError: Failed to launch com.my-company.Test | ================================== | | [Remote] CouldNotLoadInputObjectFile: Could not load object file during preview: /Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o | | | | path: /Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o | | | | ================================== | | | [Remote] XOJITError | | | | | | XOJITError: '/Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o': No such file or directory It appears that the preview process cannot find the compiled .o files. However, when I check in Finder, the files do exist and normally running the app works fine. It is noteworthy that this is independent of the XCode project or view I try to preview. It is a global issue on my system. Previews not even work when I create a blank new SwiftUI project in XCode. I tried deleting all caches, derived data, preview caches etc. But without any effect. I have this in XCode 16.3 as well as in 16.4 RC. On macOS Sequoia 15.4.1 on a MacBook Air M4. Does anybody have an idea what might be causing this?
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Aug ’25
Preview crashes when using ForEach with a Binding to an array and generics
The following repro case results in a previews crash on Xcode 26 beta 3 (report attached). FB18762054 import SwiftUI final class MyItem: Identifiable, Labelled { var label: String init(_ label: String) { self.label = label } } protocol Labelled { var label: String { get } } struct HelloView: View { let label: String var body: some View { Text(label) } } struct ListView<Element: Labelled & Identifiable>: View { @Binding var elements: [Element] var body: some View { List { ForEach($elements, id: \.id) { $element in HelloView(label: element.label) // crash // Replacing the above with a predefined view works correctly // Text(element.label) } } } } struct ForEachBindingRepro: View { @State var elements: [MyItem] = [ MyItem("hello"), MyItem("world"), ] var body: some View { ListView(elements: $elements) } } #Preview("ForEachBindingRepro") { ForEachBindingRepro() } foreachbindingrepro-2025-07-12-020628.ips
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Jul ’25
Using @Environment for a router implementation...
Been messing with this for a while... And cannot figure things out... Have a basic router implemented... import Foundation import SwiftUI enum Route: Hashable { case profile(userID: String) case settings case someList case detail(id: String) } @Observable class Router { var path = NavigationPath() private var destinations: [Route] = [] var currentDestination: Route? { destinations.last } var navigationHistory: [Route] { destinations } func navigate(to destination: Route) { destinations.append(destination) path.append(destination) } } And have gotten this to work with very basic views as below... import SwiftUI struct ContentView: View { @State private var router = Router() var body: some View { NavigationStack(path: $router.path) { VStack { Button("Go to Profile") { router.navigate(to: .profile(userID: "user123")) } Button("Go to Settings") { router.navigate(to: .settings) } Button("Go to Listings") { router.navigate(to: .someList) } .navigationDestination(for: Route.self) { destination in destinationView(for: destination) } } } .environment(router) } @ViewBuilder private func destinationView(for destination: Route) -&gt; some View { switch destination { case .profile(let userID): ProfileView(userID: userID) case .settings: SettingsView() case .someList: SomeListofItemsView() case .detail(id: let id): ItemDetailView(id: id) } } } #Preview { ContentView() } I then have other views named ProfileView, SettingsView, SomeListofItemsView, and ItemDetailView.... Navigation works AWESOME from ContentView. Expanding this to SomeListofItemsView works as well... Allowing navigation to ItemDetailView, with one problem... I cannot figure out how to inject the Canvas with a router instance from the environment, so it will preview properly... (No idea if I said this correctly, but hopefully you know what I mean) import SwiftUI struct SomeListofItemsView: View { @Environment(Router.self) private var router var body: some View { VStack { Text("Some List of Items View") Button("Go to Item Details") { router.navigate(to: .detail(id: "Test Item from List")) } } } } //#Preview { // SomeListofItemsView() //} As you can see, the Preview is commented out. I know I need some sort of ".environment" added somewhere, but am hitting a wall on figuring out exactly how to do this. Everything works great starting from contentview (with the canvas)... previewing every screen you navigate to and such, but you cannot preview the List view directly. I am using this in a few other programs, but just getting frustrated not having the Canvas available to me to fine tune things... Especially when using navigation on almost all views... Any help would be appreciated.
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Jul ’25
Unable to create SwiftUI previews in Xcode 26 for iOS 15.5
I am getting this error msg when I try to run a SwiftUI Preview on an iOS 15.5 simulator: Termination Reason: Namespace DYLD, Code 1, Library missing | Library not loaded: /usr/lib/swift/libswift_StringProcessing.dylib | Referenced from: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator/libLiveExecutionResultsLogger.dylib | Reason: tried: '/Users/hfg/Library/Developer/Xcode/DerivedData/Testios15sim-aawlbfbtggzozseoekycwwpadhrc/Build/Intermediates.noindex/Previews/iphonesimulator/Testios15sim/Products/Debug-iphonesimulator/libswift_StringProcessing.dylib' (no such file), '/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 15.5.simruntime/Contents/Resources/RuntimeRoot/usr/lib/swift/libswift_StringProcessing.dylib' (no such file), '/usr/lib/swift/libswift_StringProcessing.dylib' (no such file), '/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 15.5.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libswift_StringProcessing.dylib' (no such file) FYI I tried with the Legacy Preview Execution both on and off
Replies
1
Boosts
1
Views
497
Activity
Nov ’25
Cannot Preview in this file. Simulator was shutdown during an update.
Hello, I am facing a recurring issue with Xcode iOS simulator (preview). I want to preview a SwiftUI for iOS in Xcode, but the Simulator app fails to boot up. I receive the follow error in Xcode: Cannot Preview in this file. Simulator was shutdown during an update. I have tried the following: Uninstall Xcode and reinstall it again Deleting all developer data Deleting Xcode cache Reinstalling iOS Simulator runtimes and reconfiguration of simulators. Tested using different simulator and runtime versions. "xcrun simctl --set previews delete al" I reported the issue: FB20485454 FB20987522 Thank you. Best regards, Jens
Replies
0
Boosts
0
Views
412
Activity
Nov ’25
Missing Context menu items in Xcode 26 on a fresh project
When following the official SwiftUI Tutorial "Landmarks", I should be able to Cmd-Ctrl-Click an element of a preview in Selectable mode to view a list of options. But Xcode shows only one option (Embed). Furthermore, if I try to type anything the popover breaks completely and grows in length infinitely. I am not sure whether this is a bug, or I missed something when installing Xcode, or both
Replies
2
Boosts
0
Views
664
Activity
Nov ’25
iOS Simulator in Xcode 26.1 makes ReportCrash process run at 60-160% of CPU
My MBP M1 Pro gets really hot. iOS 26.1 Simulator in Xcode 26.1 makes ReportCrash process run at 60-160% of CPU shows Activity Monitor. MacOS 26.1. I've reported this via Feedback Assistant: FB20918609. Is there a way to quit this process permanently? When I Force Quit this it opens again immediately. Only way to stop it is to quit Simulator. But then again, I need to use the Simulator.
Replies
3
Boosts
9
Views
1.5k
Activity
Nov ’25
Build Issue
I am trying to make build for my project followed all step and all but Igot Showing Recent Errors Only Build target PCS_EmpApp of project PCS_EmpApp with configuration Debug ProcessInfoPlistFile /Users/mayankjain/Library/Developer/Xcode/DerivedData/PCS_EmpApp-bhccfqkphneiyabcysmesvskjrrm/Build/Products/Debug-iphonesimulator/PCS_EmpApp.app/Info.plist /Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync/Info.plist (in target 'PCS_EmpApp' from project 'PCS_EmpApp') cd /Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync builtin-infoPlistUtility /Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync/Info.plist -producttype com.apple.product-type.application -genpkginfo /Users/mayankjain/Library/Developer/Xcode/DerivedData/PCS_EmpApp-bhccfqkphneiyabcysmesvskjrrm/Build/Products/Debug-iphonesimulator/PCS_EmpApp.app/PkgInfo -expandbuildsettings -format binary -platform iphonesimulator -o /Users/mayankjain/Library/Developer/Xcode/DerivedData/PCS_EmpApp-bhccfqkphneiyabcysmesvskjrrm/Build/Products/Debug-iphonesimulator/PCS_EmpApp.app/Info.plist error: Build input file cannot be found: '/Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync/Info.plist'. Did you forget to declare this file as an output of a script phase or custom build rule which produces it? (in target 'PCS_EmpApp' from project 'PCS_EmpApp') Build input file cannot be found: '/Users/mayankjain/Downloads/RetailApp/PCS_EmpApp/obj/Debug/net9.0-ios/iossimulator-arm64/xcsync/Info.plist'. Did you forget to declare this file as an output of a script phase or custom build rule which produces it? error . I tried but unable to solve it .
Replies
1
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0
Views
310
Activity
Nov ’25
XCPreviewAgent crashes with KERN_PROTECTION_FAILURE on macOS 26.0.1 Tahoe
Hello, I'm experiencing consistent crashes of XCPreviewAgent when using Xcode Previews on macOS 26.0.1 Tahoe (25A362). Configuration: macOS: 26.0.1 (25A362) - stable release Xcode: 16.0 (23.0.54) - stable release Hardware: MacBook Pro M4 Project: SwiftUI iOS app Issue: Every time I try to use Xcode Previews, XCPreviewAgent crashes with: Exception Type: EXC_BAD_ACCESS (SIGBUS) Exception Subtype: KERN_PROTECTION_FAILURE at 0x0000000340e54000 Termination Reason: Namespace SIGNAL, Code 10, Bus error: 10 The crash occurs in shared memory region during dynamic library loading. What I've tried: Cleared all caches: rm -rf ~/Library/Developer/Xcode/DerivedData Deleted Preview data: rm -rf ~/Library/Developer/Xcode/UserData/Previews Reset simulators: xcrun simctl --set previews delete all Switched xcode-select to /Applications/Xcode.app/Contents/Developer Tried both Xcode stable and Xcode beta Created fresh simulators Clean build (Cmd+Shift+K) Rebooted Mac multiple times The app runs fine on simulator (Cmd+R), but Previews consistently crash.
Replies
1
Boosts
0
Views
286
Activity
Oct ’25
Simulator causing Mac audio distortion
I am experiencing an issue where my Mac's speakers will crackle and pop when running an app on the Simulator or even when previewing SwiftUI with Live Preview. I am using a 16" MacBook Pro (i9) and I'm running Xcode 12.2 on Big Sur (11.0.1). Killing coreaudiod temporarily fixes the problem however this is not much of a solution. Is anyone else having this problem?
Replies
17
Boosts
7
Views
13k
Activity
Oct ’25
SwiftUI macOS Preview Crash When Using Custom Row Directly Inside List
I’ve hit a strange SwiftUI preview crash that happens on macOS previews when using a view inside a List’s ForEach, resulting in the error Fatal Error in TableViewListCore_Mac2.swift. Only crashes macOS preview - iPhone/iPad preview doesn't crash. Doesn't crash when actually running the app. Here’s a minimal reproducible example, causing the preview to crash. XCode: Version 26.0.1 (17A400) MacOS: 26.0.1 (25A362) import SwiftUI struct Item: Identifiable { let id = UUID() let name: String } struct ItemRow: View { let item: Item var body: some View { HStack { Button(action: {}) { Image(systemName: "play") } Text(item.name) Spacer() ProgressView() } } } struct ContentView: View { @State private var items = [ Item(name: "Item A"), Item(name: "Item B"), ] var body: some View { List { ForEach(items) { item in ItemRow(item: item) } } } } #Preview("Content view") { ContentView() } #Preview("Item row") { ItemRow(item: Item(name: "Item A")) } If I wrap the row in a container, like this: ForEach(items) { item in ZStack { ItemRow(item: item) } } the crash seems to disappear. Has anyone else seen this behavior? What might I be doing wrong? Any ideas about what could be causing this?
Replies
1
Boosts
1
Views
403
Activity
Oct ’25
Mergeable library is not compatible with SwiftUI preview
When I enable the Mergeable library in Xcode, SwiftUI preview will be not available, and the error is as follows. Cannot preview in this file Could not analyze the built target description for Demo to create the preview. arguments: -no_merge_framework: Failed parsing Mach-O file Assets Report
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2
Boosts
0
Views
397
Activity
Sep ’25
Duplicate apps launched when debugging in Xcode?
I’ve noticed a strange bug in Xcode 16 and Swift. When a preview is rendering and hasn’t finished yet and you run an app to debug, Xcode is launching two instances of the app. Has anyone else noticed this issue? If you let the preview finish rendering before running the app, this doesn’t happen. Very odd.
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24
Boosts
21
Views
3.3k
Activity
Sep ’25
SwiftUI #Previews: How to populate with data
Suppose you have a view: struct Library: View { @State var books = [] var body: some View { VStack { ... Button("add Book") { .... } } } Such that Library view holds a Book array that gets populated internally via a button that opens a modal – or something alike. How can I use #Peviews to preview Library with a pre-populated collection? Suppose I have a static books – dummy – array in my code just for that; still, what's the best way to use that to preview the Library view?
Replies
4
Boosts
0
Views
371
Activity
Sep ’25
Xcode Simulator Can't Boot
I am facing a recurring issue with Xcode iOS simulator. I want to preview a SwiftUI for iOS in Xcode, but the Simulator app fails to boot up. I receive the follow error in Xcode: Cannot Preview in this file. Simulator was shutdown during an update. I have tried the following: Deleting Xcode cache Reinstalling iOS Simulator runtimes Completely uninstalling Xcode and deleting all developer data, then reinstalling None of the above steps fix the problem. The only fix I have found is to completely reinstall MacOS 15.4.1. THIS IS TERRIBLE! I have already reinstalled MacOS 15.4.1 once to fix the issue, and I don't want to do it again. If there is another solution, please help me find it! Thank you!!
Replies
15
Boosts
2
Views
761
Activity
Aug ’25
XCPreviewAgent crashed with some SwiftUI View
The steps to reproduce this issue are a bit complicated. In my app, previewing View A in Package P works fine, but another view in the same package fails to preview. The error message is shown below. It seems that the memory used for the preview is interfering with the shared memory area. This is reported as FB18519266 Exception Subtype: KERN_PROTECTION_FAILURE at 0x00000003402d8900 Exception Codes: 0x0000000000000002, 0x00000003402d8900 VM Region Info: 0x3402d8900 is in 0x3402c8000-0x340a18000; bytes after start: 67840 bytes before end: 7599871 REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL mapped file 3401dc000-3402c8000 [ 944K] r-x/rwx SM=COW Object_id=57e4ac ---> shared memory 3402c8000-340a18000 [ 7488K] rw-/rw- SM=SHM mapped file 340a18000-340f38000 [ 5248K] r-x/rwx SM=COW Object_id=1dc9a049 Termination Reason: ****** 10 Bus error: 10 Terminating Process: exc handler [94787]
Replies
3
Boosts
0
Views
312
Activity
Aug ’25
Xcode restarts my Macbook when previewing canvas
I have an issue with Xcode that it crashes my Macbook and restarts it instantly when I unpause the preview canvas. I managed to make it run for a minute longer by not watching a youtube video. I am writing a very simple SwiftUI project for iOS nothing too big to warrant any issues. Does anyone have a solution to fix this? Macbook Pro M3 16GB RAM, 500GB SSD (plenty of storage space) Tahoe 26.0
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1
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0
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261
Activity
Aug ’25
Xcode forces my Macbook to restart when previewing canvas
I can't use Xcode without it crashing. Just writing a very simple iOS app with SwiftUI (using only forms and sections). Whenever my canvas updates to correspond to my changes it forces my Macbook to restart. Does anyone have a solution for this. I'll be honest it's becoming really frustrating. Thank you. Macbook M3 Pro 16GB ram, 500gb Space (400gb free space)
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1
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0
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228
Activity
Aug ’25
Using Previews causes a system crash on Xcode 26 Beta 4 and MacOS 26 Beta 4
Hey, I've updated to both Xcode 26 Beta 4 and MacOS 26 Beta 4. Both run super stable so far. However, every time I use Xcode Previews for a few minutes, the entire system freezes for a few seconds and then crashes and reboots. I'm trying to generate a system diagnosis (which it offers me after the reboot), but it seems to be stuck generating. It's hard to say what exactly causes the crash, unfortunately. But it happened multiple times after starting to use Xcode Previews. Anyone else has that problem? I've also filed a feedback for this: FB19013059 Cheers Dennis
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11
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12
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998
Activity
Aug ’25
Previews globally fail with CouldNotLoadInputObjectFile error
Whenever I try to use SwiftUI previews, the preview fails with a CouldNotLoadInputObjectFile error like this: == PREVIEW UPDATE ERROR: FailedToLaunchAppError: Failed to launch com.my-company.Test | ================================== | | [Remote] CouldNotLoadInputObjectFile: Could not load object file during preview: /Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o | | | | path: /Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o | | | | ================================== | | | [Remote] XOJITError | | | | | | XOJITError: '/Users/me/Library/Developer/Xcode/DerivedData/Test-dzmdthicvcbuwkawncuacsomcdcd/Build/Intermediates.noindex/Test.build/Debug-iphonesimulator/Test.build/Objects-normal/arm64/TestApp.o': No such file or directory It appears that the preview process cannot find the compiled .o files. However, when I check in Finder, the files do exist and normally running the app works fine. It is noteworthy that this is independent of the XCode project or view I try to preview. It is a global issue on my system. Previews not even work when I create a blank new SwiftUI project in XCode. I tried deleting all caches, derived data, preview caches etc. But without any effect. I have this in XCode 16.3 as well as in 16.4 RC. On macOS Sequoia 15.4.1 on a MacBook Air M4. Does anybody have an idea what might be causing this?
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3
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2
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449
Activity
Aug ’25
Preview crashes when using ForEach with a Binding to an array and generics
The following repro case results in a previews crash on Xcode 26 beta 3 (report attached). FB18762054 import SwiftUI final class MyItem: Identifiable, Labelled { var label: String init(_ label: String) { self.label = label } } protocol Labelled { var label: String { get } } struct HelloView: View { let label: String var body: some View { Text(label) } } struct ListView<Element: Labelled & Identifiable>: View { @Binding var elements: [Element] var body: some View { List { ForEach($elements, id: \.id) { $element in HelloView(label: element.label) // crash // Replacing the above with a predefined view works correctly // Text(element.label) } } } } struct ForEachBindingRepro: View { @State var elements: [MyItem] = [ MyItem("hello"), MyItem("world"), ] var body: some View { ListView(elements: $elements) } } #Preview("ForEachBindingRepro") { ForEachBindingRepro() } foreachbindingrepro-2025-07-12-020628.ips
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6
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0
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429
Activity
Jul ’25
Using @Environment for a router implementation...
Been messing with this for a while... And cannot figure things out... Have a basic router implemented... import Foundation import SwiftUI enum Route: Hashable { case profile(userID: String) case settings case someList case detail(id: String) } @Observable class Router { var path = NavigationPath() private var destinations: [Route] = [] var currentDestination: Route? { destinations.last } var navigationHistory: [Route] { destinations } func navigate(to destination: Route) { destinations.append(destination) path.append(destination) } } And have gotten this to work with very basic views as below... import SwiftUI struct ContentView: View { @State private var router = Router() var body: some View { NavigationStack(path: $router.path) { VStack { Button("Go to Profile") { router.navigate(to: .profile(userID: "user123")) } Button("Go to Settings") { router.navigate(to: .settings) } Button("Go to Listings") { router.navigate(to: .someList) } .navigationDestination(for: Route.self) { destination in destinationView(for: destination) } } } .environment(router) } @ViewBuilder private func destinationView(for destination: Route) -&gt; some View { switch destination { case .profile(let userID): ProfileView(userID: userID) case .settings: SettingsView() case .someList: SomeListofItemsView() case .detail(id: let id): ItemDetailView(id: id) } } } #Preview { ContentView() } I then have other views named ProfileView, SettingsView, SomeListofItemsView, and ItemDetailView.... Navigation works AWESOME from ContentView. Expanding this to SomeListofItemsView works as well... Allowing navigation to ItemDetailView, with one problem... I cannot figure out how to inject the Canvas with a router instance from the environment, so it will preview properly... (No idea if I said this correctly, but hopefully you know what I mean) import SwiftUI struct SomeListofItemsView: View { @Environment(Router.self) private var router var body: some View { VStack { Text("Some List of Items View") Button("Go to Item Details") { router.navigate(to: .detail(id: "Test Item from List")) } } } } //#Preview { // SomeListofItemsView() //} As you can see, the Preview is commented out. I know I need some sort of ".environment" added somewhere, but am hitting a wall on figuring out exactly how to do this. Everything works great starting from contentview (with the canvas)... previewing every screen you navigate to and such, but you cannot preview the List view directly. I am using this in a few other programs, but just getting frustrated not having the Canvas available to me to fine tune things... Especially when using navigation on almost all views... Any help would be appreciated.
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2
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0
Views
379
Activity
Jul ’25
Cannot select individual view in selectable mode
Cannot select individual view in selectable mode in Xcode preview, it only show the whole blue device border.
Replies
4
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2
Views
1.1k
Activity
Jul ’25