This seems fixed with xcode Version 16.4 (16F6)

Bingo. Xcode Version 16.3 (16E140) New iOS App project, iOS 18.4, edit Scheme, switch on: address sanitizer, detect use of stack after return, undefined behavior sanitizer, main thread checker thread performance checker malloc scribble zombie objects api validation And you get (iPhone 13 iOS 18.4 simulator): `libclang_rt.asan_iossim_dynamic.dylib`__sanitizer::MemoryMappingLayout::Next: 0x1100d9e50 <+0>: cmpl $-0x1, 0x8(%rdi) 0x1100d9e54 <+4>: jl 0x1100d9e7b ; <+43> 0x1100d9e56 <+6>: pushq %rbp 0x1100d9e57 <+7>: movq %rsp, %rbp 0x1100d9e5a <+10>: pushq %r15 0x1100d9e5c <+12>: pushq %r14 ... 0x1100d9f54 <+260>: movl 0x4(%r13), %eax 0x1100d9f58 <+264>: addq %rax, %r13 -> 0x1100d9f5b <+267>: movl (%r13), %eax 0x1100d9f5f <+271>: cmpl $0xc, %eax 0x1100d9f62 <+274>: jne 0x1100d9f50 ; <+256> ` If you modify the App to run on iOS 18.0 (minimum deployment), add a simulator for iOS 18.0, you will find it runs fine on 18.0, with all those sanitizers on. Will attach project to bug, eh feedback report FB17723761

Going to file a bug report, I think it is a bug in Xcode.

(In the App Analytics in AppstoreConnect I see no increase in the number of crashes for this app, 375k sessions/month, 98 crashes, so 0.25 promille.)

Thanks Quinn, I'm sure a new and clean empty project runs, but this is a (big) existing project, objective-c, no storyboard but XIBs, that has run fine before 18.4, for years. As the crash happens before my code is even entered I don't even know where to start! Does this Sanitizer message mean anything to you? What is the problem with MemoryMappingLayout? libclang_rt.asan_iossim_dynamic.dylib__sanitizer::MemoryMappingLayout::Next: 0x10f2dae50 <+0>: cmpl $-0x1, 0x8(%rdi)` With the sanitizers switched off in the Run Scheme the app runs fine in the Simulator, but I have a user that experiences an actual crash on device. That crash is different from what I experience: the app crashes on simulator before entering my code, after displaying the splash screen, while the user has an app that does startup, and can be used for a few seconds, but crashes on a certain input. As is, I cannot even establish if these crashes are related. In the App Analytics in AppstoreConnect I see no increase in the number of crashes for this app, 375k sessions/month, 98 crashes, so 0.25 promille.

Same here, started with iOS 18.4 I think. The crash happens before main.m is even entered, breakpoint in main.m is not reached. Before 18.4 it did. Did you find a solution?

Mind that attr -c does not change the timestamp of a file, so git commit will not notice it’s changed. You also need to “touch” the file. I find the complaint about the attributes a bit lame, photoshop, safari all seem to set these attributes. Have xcode check, warn, remove such attributes in the distribution process. If it’s important enough to notify developers after upload, then please build it into xcode.

After upload got a mail from AppStoreConnect 'ITMS-91109: Invalid package contents - The package contains one or more files with the com.apple.quarantine extended file attribute'. Indeed in the past xcode complained about such files, like images saved from Photoshop that have extended attributes. Easily removed with 'xattr -c'. But, if this is an issue to send us emails about AFTER upload, then please have xcode check this BEFORE upload.. I had 3000+ such images.

I got that message about some image files: Photoshop leaves attributes on saved files. You can remove them with 'xattr -c' Apparently the check now is more rigid, never had complaints before.

I had this, caused by this: NrofWindows = [[NSWindow windowNumbersWithOptions:NSWindowNumberListAllApplications|NSWindowNumberListAllSpaces] count]; Doc says: "If you pass 0 instead, then the list the method returns contains window numbers for visible windows on the active space belonging to the calling application" As that is what I actually need, changed the value to 0: NrofWindows = [[NSWindow windowNumbersWithOptions:0] count]; And the log msg vanished. Thanks Eljay Adobe for the breakpoint command. rick

Thanks for pointing me to NSLocationUsageDescription. If it's missing from the plist you get crashes on Big Sur, but not always. The validation procedures in AppStoreConnect do not check this, apparently, I just got crash reports from the review team.