I downloaded the Xcode Beta 3 on my MacBook Pro M4 Base today and tested out some iOS26 mechanics of my app. And when I came back to my main Xcode to continue developing in iOS18, I couldn't build my app. I went to Product > Destination > Manage run destinations and then tried to create a simulator with iOS18 but it didn't show up, only choice that's showing up was iOS26. I tried deleting iOS18 platform and downloading it again but it didn't solve, I tried deleting Xcode Beta but it didn't solve the problem either. I deleted Runtimes folder, it didn't solve too. I can not create a simulator of iOS18 or below too, the error says "The iOS 18.5 simulator runtime is not available. Try reinstalling Xcode or the simulator runtime." How can I fix this problem?
I can't run or create a simulator that isn't iOS26 after downloading the Xcode Beta 3
Let's go through this one issue at a time:
"I couldn't build my app": Why not? What error(s) are you seeing? Being unable to build your app has nothing to do with running your app on a Simulator or device (other than it needing to build before you can deploy it).
"tried to create a simulator with iOS18 but it didn't show up": Meaning you don't have iOS 18.5 installed.
"I tried deleting iOS18 platform and downloading it again": Where from? Xcode > Settings > Components? That's the best place to manage your installed runtimes.
"I tried deleting Xcode Beta but it didn't solve the problem": The Xcode and Xcode-beta apps are entirely separate from the installed runtimes. The runtimes are installed in a separate location, which is very flexible because it saves disk space by allowing them to be shared between any installed Xcode apps.
"I deleted Runtimes folder, it didn't solve": Don't do this. Use Xcode's Settings > Components to manage your runtimes.
So, let me know what's listed in your Xcode (not Xcode-beta) app's Settings > Components window. If iOS 18.5 is listed but not installed, try clicking "Get" to install it.
I am using XCode version 26.0.1 (17A400). I have downloaded iOS 18.6, but I still cannot create emulators below version 26.0. please help me
How to solve
The screen shots are from xcode 26. You need to close and quit xcode. Open xcode 16.x from the applications folder. open the xcode | settings menu. Click on the locations tab. In the command line tools, select the xcode 16.x version. Then go to the components tab. You should see components for older ios versions.
I would open your project. Tap on the xcode | about xcode to be sure you are seeing xcode 16.x
Select the target you want and device/simulator you want.
Try building/running your project.
I have re downloaded xcode16, but the emulator still cannot create versions lower than ios26