I have this exception backtrace in my app. I'm not sure if this crash is from my implementation or from the OS. From the frame 2 we can see that this is the one that throwing exception, but I still have no idea about it. Does anyone can help? Thanks Here is the back complete crash log and the backtrace: 2023-07-20_10-12-23.5237_+0700-e3c7635495de265f5efcc92a0d27dd1d0f7bede7.crash Last Exception Backtrace: 0 CoreFoundation 0x1b6838d78 __exceptionPreprocess + 220 (NSException.m:200) 1 libobjc.A.dylib 0x1cf49d734 objc_exception_throw + 60 (objc-exception.mm:565) 2 CoreFoundation 0x1b6890024 +[NSException raise:format:] + 112 (NSException.m:156) 3 UIKitCore 0x1b9617e20 -[UIDocument writeContents:toURL:forSaveOperation:originalContentsURL:error:] + 616 (UIDocument.m:1329) 4 UIKitCore 0x1b9617a9c -[UIDocument writeContents:andAttributes:safelyToURL:forSaveOperation:error:] + 492 (UIDocument.m:1286) 5 UIKitCore 0x1b9619264 __59-[UIDocument saveToURL:forSaveOperation:completionHandler:]_block_invoke_3 + 224 (UIDocument.m:1490) 6 UIKitCore 0x1b96190cc __59-[UIDocument saveToURL:forSaveOperation:completionHandler:]_block_invoke_2 + 380 (UIDocument.m:1524) 7 UIKitCore 0x1b961865c __59-[UIDocument _coordinateWritingItemAtURL:error:byAccessor:]_block_invoke.623 + 184 (UIDocument.m:1407) 8 Foundation 0x1b803cf98 -[NSFileCoordinator _invokeAccessor:thenCompletionHandler:] + 100 (NSFileCoordinator.m:430) 9 Foundation 0x1b8083774 __73-[NSFileCoordinator coordinateWritingItemAtURL:options:error:byAccessor:]_block_invoke + 132 (NSFileCoordinator.m:473) 10 Foundation 0x1b8194e30 __85-[NSFileCoordinator(NSPrivate) _coordinateWritingItemAtURL:options:error:byAccessor:]_block_invoke.350 + 264 (NSFileCoordinator.m:1083) 11 Foundation 0x1b8073538 -[NSFileCoordinator(NSPrivate) _withAccessArbiter:invokeAccessor:orDont:andRelinquishAccessClaim:] + 620 (NSFileCoordinator.m:960) 12 Foundation 0x1b80866c0 -[NSFileCoordinator(NSPrivate) _coordinateWritingItemAtURL:options:error:byAccessor:] + 784 (NSFileCoordinator.m:1080) 13 Foundation 0x1b7fa0710 -[NSFileCoordinator coordinateWritingItemAtURL:options:error:byAccessor:] + 120 (NSFileCoordinator.m:472) 14 UIKitCore 0x1b9618288 -[UIDocument _coordinateWritingItemAtURL:error:byAccessor:] + 472 (UIDocument.m:1404) 15 UIKitCore 0x1b9618cd8 __59-[UIDocument saveToURL:forSaveOperation:completionHandler:]_block_invoke + 336 (UIDocument.m:1476) 16 libdispatch.dylib 0x1b649de68 _dispatch_call_block_and_release + 32 (init.c:1517) 17 libdispatch.dylib 0x1b649fa2c _dispatch_client_callout + 20 (object.m:560) 18 libdispatch.dylib 0x1b64a7124 _dispatch_lane_serial_drain + 668 (inline_internal.h:2622) 19 libdispatch.dylib 0x1b64a7c80 _dispatch_lane_invoke + 392 (queue.c:3944) 20 libdispatch.dylib 0x1b64b2500 _dispatch_workloop_worker_thread + 648 (queue.c:6732) 21 libsystem_pthread.dylib 0x2278420bc _pthread_wqthread + 288 (pthread.c:2599) 22 libsystem_pthread.dylib 0x227841e5c start_wqthread + 8 (:-1)