Unable to create SwiftUI previews in Xcode 26 for iOS 15.5

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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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Answer 1

Developer Tools Engineer OP

Apple

20h

Hi,

Sorry to hear you are having problems getting previews working. The best next step will be to file a feedback with diagnostics so we can take a look at the underlying details of the issue.

We will need the diagnostics Xcode Previews generates in order to make sure we understand the error the previews system is encountering.

Install the logging profile using instructions available here: https://developer.apple.com/bug-reporting/profiles-and-logs/?name=swift On your mac running Xcode, and on your physical preview device (if you are using one).

Install the logging profile using the following instructions on your mac running Xcode; and if you are using one, your physical preview device (iOS or visionOS): https://developer.apple.com/bug-reporting/profiles-and-logs/?name=swift

Then when you reproduce the problem in Xcode:

Either (a) an error banner will appear, click the "Diagnostics" button in that banner; or (b) if you're not seeing an error but you still want to provide diagnostics you can get the same diagnostics window by going under the Editor menu in the menu bar, then selecting the Canvas submenu, then selecting "Diagnostics".
In the sheet that appears, click "Generate Report" in the bottom left of the sheet
Attach (or make from the folder) the resulting zip file to the bug (will be named something like previews-diagnostics-0123456789.zip)
Generate a sysdiagnose on your mac and any on-device preview devices, and attach those too

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