App crashing randomly on start-up

I've been encountering a strange crash that occurs randomly on my app's startup. The app compiles and (usually) runs just fine but every so often will close out immediately within a second or two of launching. I have found no methods to consistently reproduce this crash.

Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Termination Reason: SIGNAL 6 Abort trap: 6

Last Exception Backtrace:
0   CoreFoundation                	       0x1a5498870 __exceptionPreprocess + 164
1   libobjc.A.dylib               	       0x19d7fbc00 objc_exception_throw + 60
2   CoreFoundation                	       0x1a551d4f8 -[NSException init] + 0
3   Foundation                    	       0x1a439877c -[NSObject(NSKeyValueCoding) setValue:forKey:] + 284
4   UIKitCore                     	       0x1a796b188 -[UIViewController setValue:forKey:] + 80
5   UIKitCore                     	       0x1a796b10c -[UIRuntimeOutletConnection connect] + 84

I would include the full crash report but for the URL needed for file attachments contains sensitive language somehow?? Any help resolving this issue would be greatly appreciated.

Answered by DTS Engineer in 787986022

The presence of the Last Exception Backtrace section indicates that your app crashed due to an unhandled language exception. Consider its backtrace:

Last Exception Backtrace:
0   CoreFoundation    … __exceptionPreprocess + 164
1   libobjc.A.dylib   … objc_exception_throw + 60
2   CoreFoundation    … -[NSException init] + 0
3   Foundation        … -[NSObject(NSKeyValueCoding) setValue:forKey:] + 284
4   UIKitCore         … -[UIViewController setValue:forKey:] + 80
5   UIKitCore         … -[UIRuntimeOutletConnection connect] + 84
6   CoreFoundation    … -[NSArray makeObjectsPerformSelector:] + 208
7   UIKitCore         … -[UINib instantiateWithOwner:options:] + 1424
8   UIKitCore         … -[UIViewController loadView] + 396
9   UIKitCore         … -[UIViewController loadViewIfRequired] + 156
10 UIKitCore          … -[UIViewController view] + 24
11 UIKitCore          … -[UIWindow addRootViewControllerViewIfPossible] + 136
12 UIKitCore          … -[UIWindow _updateLayerOrderingAndSetLayerHidden:actionBlock:] + 216
13 UIKitCore          … -[UIWindow _setHidden:forced:] + 256
14 UIKitCore          … -[UIWindow _mainQueue_makeKeyAndVisible] + 40
15 UIKitCore          … -[UIWindowScene _performDeferredInitialWindowUpdateForConnection] + 208
16 UIKitCore          … +[UIScene _sceneForFBSScene:create:withSession:connectionOptions:] + 1232
17 UIKitCore          … -[UIApplication _connectUISceneFromFBSScene:transitionContext:] + 808
18 UIKitCore          … -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] + 360
19 UIKitCore          … -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] + 288
20 FrontBoardServices … -[FBSScene _callOutQueue_didCreateWithTransitionContext:completion:] + 324
21 FrontBoardServices … __92-[FBSWorkspaceScenesClient createSceneWithIdentity:parameters:transitionContext:com…
22 FrontBoardServices … -[FBSWorkspace _calloutQueue_executeCalloutFromSource:withBlock:] + 168
23 FrontBoardServices … __92-[FBSWorkspaceScenesClient createSceneWithIdentity:parameters:transitionContext:com…
24 libdispatch.dylib  … _dispatch_client_callout + 20
25 libdispatch.dylib  … _dispatch_block_invoke_direct + 284
26 FrontBoardServices … __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 52
27 FrontBoardServices … -[FBSMainRunLoopSerialQueue _targetQueue_performNextIfPossible] + 240
28 FrontBoardServices … -[FBSMainRunLoopSerialQueue _performNextFromRunLoopSource] + 28
29 CoreFoundation     … __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28
30 CoreFoundation     … __CFRunLoopDoSource0 + 176
31 CoreFoundation     … __CFRunLoopDoSources0 + 340
32 CoreFoundation     … __CFRunLoopRun + 828
33 CoreFoundation     … CFRunLoopRunSpecific + 608
34 GraphicsServices   … GSEventRunModal + 164
35 UIKitCore          … -[UIApplication _run] + 888
36 UIKitCore          … UIApplicationMain + 340
37 iDentify           … main + 64
38 dyld               … start + 2240

Frames 3 through 0 are what you see when you try to set a property on an object that doesn’t support that property. Frame 5 suggests that this is UIKit trying to ‘wire up’ an IBOutlet. It’s hard to say much beyond that.

If you can get this to crash when the debugging is attached, Xcode should show the actual exception message. That’ll tell you which outlet was involved.

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

It’s hard to say what’s going on here based on the info available here. Please post a full Apple crash report, per the advice in Posting a Crash Report.

I would include the full crash report but for the URL needed for file attachments contains sensitive language somehow?

Try posting it in a reply. I’ve been tracking an issue where DevForums rejects a crash report in an initial post but then allows the same crash report in a reply. It’ll be interesting to see if that matches your experience.

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Thanks for the quick reply, here's the full crash report:

Accepted Answer

The presence of the Last Exception Backtrace section indicates that your app crashed due to an unhandled language exception. Consider its backtrace:

Last Exception Backtrace:
0   CoreFoundation    … __exceptionPreprocess + 164
1   libobjc.A.dylib   … objc_exception_throw + 60
2   CoreFoundation    … -[NSException init] + 0
3   Foundation        … -[NSObject(NSKeyValueCoding) setValue:forKey:] + 284
4   UIKitCore         … -[UIViewController setValue:forKey:] + 80
5   UIKitCore         … -[UIRuntimeOutletConnection connect] + 84
6   CoreFoundation    … -[NSArray makeObjectsPerformSelector:] + 208
7   UIKitCore         … -[UINib instantiateWithOwner:options:] + 1424
8   UIKitCore         … -[UIViewController loadView] + 396
9   UIKitCore         … -[UIViewController loadViewIfRequired] + 156
10 UIKitCore          … -[UIViewController view] + 24
11 UIKitCore          … -[UIWindow addRootViewControllerViewIfPossible] + 136
12 UIKitCore          … -[UIWindow _updateLayerOrderingAndSetLayerHidden:actionBlock:] + 216
13 UIKitCore          … -[UIWindow _setHidden:forced:] + 256
14 UIKitCore          … -[UIWindow _mainQueue_makeKeyAndVisible] + 40
15 UIKitCore          … -[UIWindowScene _performDeferredInitialWindowUpdateForConnection] + 208
16 UIKitCore          … +[UIScene _sceneForFBSScene:create:withSession:connectionOptions:] + 1232
17 UIKitCore          … -[UIApplication _connectUISceneFromFBSScene:transitionContext:] + 808
18 UIKitCore          … -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] + 360
19 UIKitCore          … -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] + 288
20 FrontBoardServices … -[FBSScene _callOutQueue_didCreateWithTransitionContext:completion:] + 324
21 FrontBoardServices … __92-[FBSWorkspaceScenesClient createSceneWithIdentity:parameters:transitionContext:com…
22 FrontBoardServices … -[FBSWorkspace _calloutQueue_executeCalloutFromSource:withBlock:] + 168
23 FrontBoardServices … __92-[FBSWorkspaceScenesClient createSceneWithIdentity:parameters:transitionContext:com…
24 libdispatch.dylib  … _dispatch_client_callout + 20
25 libdispatch.dylib  … _dispatch_block_invoke_direct + 284
26 FrontBoardServices … __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 52
27 FrontBoardServices … -[FBSMainRunLoopSerialQueue _targetQueue_performNextIfPossible] + 240
28 FrontBoardServices … -[FBSMainRunLoopSerialQueue _performNextFromRunLoopSource] + 28
29 CoreFoundation     … __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28
30 CoreFoundation     … __CFRunLoopDoSource0 + 176
31 CoreFoundation     … __CFRunLoopDoSources0 + 340
32 CoreFoundation     … __CFRunLoopRun + 828
33 CoreFoundation     … CFRunLoopRunSpecific + 608
34 GraphicsServices   … GSEventRunModal + 164
35 UIKitCore          … -[UIApplication _run] + 888
36 UIKitCore          … UIApplicationMain + 340
37 iDentify           … main + 64
38 dyld               … start + 2240

Frames 3 through 0 are what you see when you try to set a property on an object that doesn’t support that property. Frame 5 suggests that this is UIKit trying to ‘wire up’ an IBOutlet. It’s hard to say much beyond that.

If you can get this to crash when the debugging is attached, Xcode should show the actual exception message. That’ll tell you which outlet was involved.

Share and Enjoy

Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Thanks for your help with this issue, I managed to get the app to crash while hooked up to the debugger and was able to determine which outlet was having issues. Changing the connected object to build for a later version of IOS seems to have solved the crashing.

App crashing randomly on start-up
 
 
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