Xcode Version 9.0.1 (9A1004) Crash with Cannot update for observer NSTouchBarFinder

Question

Opening a specific project Xcode crashes repeatably when opening specific project.

Opening another project seems fine. It seems that the touch-bar is creating some issues. Any ideas on how to resolve this.

Opening the project on a different MacBook without a touch-bar seems fine.

From the logs I can see that this is related to the NSTouchBarFinder and the IDE not being KVO compliant?

I keep getting this crash log:

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Application Specific Information:
ProductBuildVersion: 9A1004
UNCAUGHT EXCEPTION (NSInternalInconsistencyException): Cannot update for observer <NSTouchBarFinder 0x7fee281263e0> for the key path "_keyWindow.firstResponder" from <IDEApplication 0x7fee22f0b1c0>, most likely because the value for the key "_keyWindow" has changed without an appropriate KVO notification being sent. Check the KVO-compliance of the IDEApplication class.
UserInfo: (null)
Hints: 

Backtrace:
  0   __exceptionPreprocess (in CoreFoundation)
  1   DVTFailureHintExceptionPreprocessor (in DVTFoundation)
  2   objc_exception_throw (in libobjc.A.dylib)
  3   +[NSException raise:format:] (in CoreFoundation)
  4   -[NSKeyValueNestedProperty object:withObservance:didChangeValueForKeyOrKeys:recurse:forwardingValues:] (in Foundation)
  5   NSKeyValueDidChange (in Foundation)
  6   -[NSObject(NSKeyValueObserverNotification) didChangeValueForKey:] (in Foundation)
  7   -[NSApplication _setKeyWindow:] (in AppKit)
  8   -[NSWindow _changeKeyAndMainLimitedOK:] (in AppKit)
  9   -[NSWindow _makeKeyRegardlessOfVisibility] (in AppKit)
 10   NSPerformVisuallyAtomicChange (in AppKit)
 11   -[NSWindow makeKeyAndOrderFront:] (in AppKit)
 12   -[NSWindow(NSWindow_Theme) _finishDeminiaturizeFromDock:] (in AppKit)
 13   -[NSWindow(NSWindowTabbing) _doNonVisibleTabDeminimize] (in AppKit)
 14   -[NSWindowStackController handleDeminimizingWindow:] (in AppKit)
 15   -[NSWindow(NSWindowTabbing) _prepareTabbedWindowDeminimize] (in AppKit)
 16   -[NSWindow(NSWindow_Theme) _prepareToRestoreFromDock:forceActivation:wantsToBeKey:] (in AppKit)
 17   -[NSWindow(NSWindow_Theme) _doRestoreComingFromDock:forceActivation:wantsToBeKey:] (in AppKit)
 18   -[NSWindow _reallyDoOrderWindowAboveOrBelow:relativeTo:findKey:forCounter:force:isModal:] (in AppKit)
 19   -[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:] (in AppKit)
 20   -[NSWindow orderWindow:relativeTo:] (in AppKit)
 21   NSPerformVisuallyAtomicChange (in AppKit)
 22   -[NSWindowStackController _doTabSelectionAndWindowOrderingAtIndex:makeKeyAndOrderFront:justOrderFront:] (in AppKit)
 23   -[NSWindowStackController setSelectedWindow:] (in AppKit)
 24   -[NSWindow(NSWindowTabbing) _doTabbedWindowOrderFront] (in AppKit)
 25   -[NSApplication _setKeyWindow:] (in AppKit)
 26   -[NSWindow _changeKeyAndMainLimitedOK:] (in AppKit)
 27   -[NSWindow _makeKeyRegardlessOfVisibility] (in AppKit)
 28   NSPerformVisuallyAtomicChange (in AppKit)
 29   -[NSWindow makeKeyAndOrderFront:] (in AppKit)
 30   -[NSWindowController showWindow:] (in AppKit)
 31   -[IDEWorkspaceDocument setOrderedWindowControllerNames:] (in IDEKit)
 32   -[NSObject(NSKeyValueObservingPrivate) _changeValueForKeys:count:maybeOldValuesDict:usingBlock:] (in Foundation)
 33   -[NSObject(NSKeyValueObservingPrivate) _changeValueForKey:key:key:usingBlock:] (in Foundation)
 34   _NSSetObjectValueAndNotify (in Foundation)
 35   -[IDEWorkspaceDocument revertStateWithDictionary:] (in IDEKit)
 36   -[DVTStateToken _pullStateFromDictionary:] (in DVTFoundation)
 37   -[DVTStateToken pullStateFromRepository] (in DVTFoundation)
 38   -[IDEWorkspaceDocument _readFromURL:ofType:simpleFilesFocused:error:] (in IDEKit)
 39   -[IDEWorkspaceDocument readFromURL:ofType:error:] (in IDEKit)
 40   -[NSDocument _initWithContentsOfURL:ofType:error:] (in AppKit)
 41   -[NSDocument initWithContentsOfURL:ofType:error:] (in AppKit)
 42   -[IDEDocumentController makeDocumentWithContentsOfURL:ofType:error:] (in IDEKit)
 43   __97-[NSDocumentController makeDocumentWithContentsOfURL:alternateContents:ofType:completionHandler:]_block_invoke (in AppKit)
 44   -[NSDocumentController makeDocumentWithContentsOfURL:alternateContents:ofType:completionHandler:] (in AppKit)
 45   __80-[NSDocumentController openDocumentWithContentsOfURL:display:completionHandler:]_block_invoke (in AppKit)
 46   __145-[IDEDocumentController _coordinateReadingAndGetAlternateContentsForOpeningDocumentAtURL:resolvingSymlinks:thenContinueOnMainThreadWithAccessor:]_block_invoke (in IDEKit)
 47   __144-[NSDocumentController _coordinateReadingAndGetAlternateContentsForOpeningDocumentAtURL:resolvingSymlinks:thenContinueOnMainThreadWithAccessor:]_block_invoke_2.922 (in AppKit)
 48   __144-[NSDocumentController _coordinateReadingAndGetAlternateContentsForOpeningDocumentAtURL:resolvingSymlinks:thenContinueOnMainThreadWithAccessor:]_block_invoke.921 (in AppKit)
 49   __144-[NSDocumentController _coordinateReadingAndGetAlternateContentsForOpeningDocumentAtURL:resolvingSymlinks:thenContinueOnMainThreadWithAccessor:]_block_invoke_4 (in AppKit)
 50   __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ (in CoreFoundation)
 51   __CFRunLoopDoBlocks (in CoreFoundation)
 52   __CFRunLoopRun (in CoreFoundation)
 53   CFRunLoopRunSpecific (in CoreFoundation)
 54   RunCurrentEventLoopInMode (in HIToolbox)
 55   ReceiveNextEventCommon (in HIToolbox)
 56   _BlockUntilNextEventMatchingListInModeWithFilter (in HIToolbox)
 57   _DPSNextEvent (in AppKit)
 58   -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] (in AppKit)
 59   -[DVTApplication nextEventMatchingMask:untilDate:inMode:dequeue:] (in DVTKit)
 60   -[NSApplication run] (in AppKit)
 61   NSApplicationMain (in AppKit)
 62   start (in libdyld.dylib)

abort() called

OS details:

Process:               Xcode [1733]
Path:                  /Applications/Xcode.app/Contents/MacOS/Xcode
Identifier:            com.apple.dt.Xcode
Version:               9.0.1 (13249)
Build Info:            IDEFrameworks-13249000000000000~2
App Item ID:           497799835
App External ID:       823984564
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           Xcode [1733]

OS Version:            Mac OS X 10.12.6 (16G29)

Answer 1

I had the same issue this morning, even with the Xcode 9.0.0 version.

I succeeded to bypass the crash at the xcode launch by deleting the xcuserdatad folder (prefixed with your username) inside the project.xcworkspace folder.