Got an update from the Feedback FB23384318 The support asked to test with Beta 4 and I can confirm the problem is solved both with iOS 26 Beta 4 and visionOS 26 Beta 4. Great work guys. It is very useful for app developers to test on Beta versions of the new OSes while keeping current Xcode (version 26.6). Thank you.

I don't have reliability issues with UserDefaults during app launch. The issue reported is in fact related to Xcode 26.5 unable to launch directly app on OS 27 devices. I have created a new subject about it: Xcode 26.5 can't run apps on visionOS 27 and iOS 27 Beta 2

I created a new post Xcode 26.5 can't run apps on visionOS 27 and iOS 27 Beta 2 The issue is not related to UserDefaults.standard.integer(forKey: ) but is related to launching from Xcode.

Yes you are right. We develop on the production Xcode (currently 26.5), but we test on every Beta OS (currently 27 OSes Beta 2) to be sure the user experience will be fine when they will update their OS. This also allows us to report feedbacks on new bugs on the future OS before it is out. And it has already been useful ;-) Unfortunately we often don't have time to also test the next Xcode, resources are limited in statups and clients await features in the apps. This issue is Xcode 26.5 can't run apps on iOS/iPadOS and visionOS Beta 2. Do you wan't me to close the feedback and open another one on Xcode?

Hello Quinn, I do not yet test Xcode 27, I' m still using Xcode Version 26.5 (17F42). Regarding the sysdiagnoses, the one made on Vision Pro was exactly the issue described with EXC_BAD_ACCESS. But as I said, without Xcode, launching directly on the devices works fine (I didn't notice at first). And now I have the crash you describe (instead of EXC_BAD_ACCESS) on iPhone and iPad with the 27 beta with the app launched from Xcode. Searching for the new error message, I found a web page describing "Fixing OS_dispatch_mach_msg _setContext: unrecognized selector on iOS 27 by Mick MacCallum" wich is the new error I see. He says In Xcode, open Product > Scheme > Edit Scheme. Select the Run action in the sidebar, then open the Options tab. Find Queue Debugging and uncheck Enable backtrace recording. This is what I did and now the project UserDefaults27 runs fine from Xcode. To recap, this is not an error with UserDefaults on the 27 OSes. The error is in fact that running apps from Xcode Version 26.5 (17F42) crashes the app on iOS, iPadOS and visionOS 27 including Beta 2 (and perhaps other 27 OSes). This could be very useful to know for other readers of this forum, as many could have the same issue. Please, tell me what you want me to do with the feedback. Should I open a new one on Xcode, can you change its category. Please let me know. Thank you very much.

Hello Quinn, Yes the project UserDefaults27 was created especially to reproduce the issue we have in our app, but a with a short sample we could send. That's why there are only print() instead of the real logic and the update of the values back to UserDefaults. The project crashed in our environment on visionOS, iOS and iPadOS 27 Beta 1 but not on an iPhone with iOS 26.5. Today I have another issue with iOS and iPadOS which stop in the Xcode debugger, but not when launching the app. I have sent Sysdiagnoses of these. I can still reproduce on visionOS and I have also sent a Sysdiagnose. Thank you very much, don't hesitate to ask if you need anything. PS: It's an honour for me to have you working on this issue. I use your precious advice on this forum on OS X and macOS since about 15 years (perhaps less I don't remember precisely the first time I've read you). Your work is very useful. Thank you.

Hello, with the OSes 27, I get a crash at app init while calling UserDefaults.standard.integer(forKey: ) The same app does not crash on iOS/iPadOS/visionOS 26. [https://developer.apple.com/forums/thread/835484]

The problem was solved in macOS 26.3 and more. All files can again be synched with iCloud Drive.

Update : in fact all files which are packages can no longer be synched with iCloud Drive since the upgrade to macOS 26.2 : local package files are never sent to iCloud, and iCloud package files are never downloaded to the Mac drive. The xcodeproj files are packages files, but also realitycomposerpro, pages, number or bundle files are packages. A new Feedback was created as it is not only Xcode related: FB21663069

We know how bug reporting is important for good software quality. We use Feedback Assistant each time we encounter an issue. Then, we also know we never get progress reports, but we had a majority of issues solved. It's worth it. Nothing changed in our infrastructure. The only changes were macOS 26.2 and Xcode 26.2. And has we had checked, and Apple Care rechecked, we have no other sync issues, just the .xcodeproj file, and now the new project .xcodeproj file. I have updated the FB to include the zip of the file with the issue to help your Xcode team. Thank you very much for you answers.

Thnak you for you quick reply. The problem occurred in a 3 years old project after updating to macOS 26.2 (25C56) and Xcode Version 26.2 (17C52). I've created a new project : same error! All files synchronize except the .xcodeproj file. There is 19GB free on iCloud Drive, and 59GB free on the Mac. If I open the original .xcodeproj package file, copy all the included files in a folder outside, then they all synchronize on iCloud Drive except project.xcworkspace Here are the attributes of this file com.apple.FinderInfo 32 com.apple.fileprovider.fpfs#P 4 com.apple.lastuseddate#PS 16 com.apple.macl 72 It's also a package, but the time if copied outside all its file are correctly synchronized to iCloud. A feedback had been opened : FB21363976. It includes a zip with the file not syncing. Thank you.

Hello Think different As for SwiftUI, AppIntents are a kind of pseudocode, you don't see all the real code. Try: let carEntity = CarEntity(car: car) // Build, then parameter the intent let openCarIntent = OpenCarIntent() openCarIntent.target = openCarIntent return .result( value: carEntity, opensIntent: openCarIntent )

Bonjour Same issue (Handler does not support background access) with iOS 26.0 beta 1 (23A5260n).

Bonjour, HomeKit is not available is the simulators. Check the full list of missing APIs in Apple documentation Regards

Problem solved in Xcode version 16.4 (16F6) available now.