A customer sent a crashlog that clearly shows Apple's code is what's crashing on 10.14.6. There's no way I can reproduce it. So what can I do? Just submit a bug to Apple with the crashlog (although it's 10.14.6, so I doubt they care)?

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libobjc.A.dylib 0x00007fff6dc0269d objc_msgSend + 29
1 com.apple.AppKit 0x00007fff41034f8b -[NSDocument _silentlyRecoverableVariantOfSavingError:resaver:] + 40
2 com.apple.AppKit 0x00007fff415c7ce1 __85-[NSDocument(NSDocumentSaving) _saveToURL:ofType:forSaveOperation:completionHandler:]_block_invoke.856 + 620
3 com.apple.AppKit 0x00007fff415c9247 __85-[NSDocument(NSDocumentSaving) _saveToURL:ofType:forSaveOperation:completionHandler:]_block_invoke_3.916 + 209
4 com.apple.AppKit 0x00007fff41068079 __62-[NSDocumentController(NSInternal) _onMainThreadInvokeWorker:]_block_invoke_3 + 152
5 com.apple.AppKit 0x00007fff4106a834 ___NSMainRunLoopPerformBlockInModes_block_invoke + 25
6 com.apple.CoreFoundation 0x00007fff434c4ec4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
7 com.apple.CoreFoundation 0x00007fff434885e7 __CFRunLoopDoBlocks + 394
8 com.apple.CoreFoundation 0x00007fff43487d06 __CFRunLoopRun + 1174
9 com.apple.CoreFoundation 0x00007fff4348761e CFRunLoopRunSpecific + 455
10 com.apple.HIToolbox 0x00007fff426e61ab RunCurrentEventLoopInMode + 292
11 com.apple.HIToolbox 0x00007fff426e5ee5 ReceiveNextEventCommon + 603
12 com.apple.HIToolbox 0x00007fff426e5c76 _BlockUntilNextEventMatchingListInModeWithFilter + 64
13 com.apple.AppKit 0x00007fff40a7e77d _DPSNextEvent + 1135
14 com.apple.AppKit 0x00007fff40a7d46b -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 1361
15 com.apple.AppKit 0x00007fff40a77588 -[NSApplication run] + 699
16 com.apple.AppKit 0x00007fff40a66ac8 NSApplicationMain + 777
17 libdyld.dylib 0x00007fff6f3de3d5 start + 1

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Steve Mills
Drummer, Mac geek