Can't seem to track this one down. My app creates a dragging session. During drag and drop, if I drag around the screen for awhile I sometimes hit this crash.
CALayer position contains NaN: [nan nan]
2016-01-14 18:08:00.753 MY APP NAME [23373:356523] (
0 CoreFoundation 0x00007fff9b5e8ae2 __exceptionPreprocess + 178
1 libobjc.A.dylib 0x00007fff9791e73c objc_exception_throw + 48
2 CoreFoundation 0x00007fff9b5e898d +[NSException raise:format:] + 205
3 QuartzCore 0x00007fff99f5914e _ZN2CA5Layer12set_positionERKNS_4Vec2IdEEb + 152
4 QuartzCore 0x00007fff99f590ae -[CALayer setPosition:] + 44
5 HIToolbox 0x00007fff8cc5e711 _ZL20UpdateLayerPositionsP14OpaqueCoreDrag + 630
6 HIToolbox 0x00007fff8ce830f8 _Z29UnflockAnimationTimerCallbackP16__CFRunLoopTimerPv + 759
7 CoreFoundation 0x00007fff9b52ebc4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
8 CoreFoundation 0x00007fff9b52e853 __CFRunLoopDoTimer + 1075
9 CoreFoundation 0x00007fff9b5ace6a __CFRunLoopDoTimers + 298
10 CoreFoundation 0x00007fff9b4e9cd1 __CFRunLoopRun + 1841
11 CoreFoundation 0x00007fff9b4e9338 CFRunLoopRunSpecific + 296
12 CoreFoundation 0x00007fff9b570db5 CFMessagePortSendRequest + 949
13 HIServices 0x00007fff867017a8 SendDragIPCMessage + 530
14 HIServices 0x00007fff866febdd CoreDragMessageHandler + 1321
15 CoreFoundation 0x00007fff9b571238 __CFMessagePortPerform + 584
16 CoreFoundation 0x00007fff9b4f8839 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 41
17 CoreFoundation 0x00007fff9b4f87a9 __CFRunLoopDoSource1 + 473
18 CoreFoundation 0x00007fff9b4e9e1b __CFRunLoopRun + 2171
19 CoreFoundation 0x00007fff9b4e9338 CFRunLoopRunSpecific + 296
20 HIToolbox 0x00007fff8cc1f935 RunCurrentEventLoopInMode + 235
21 HIToolbox 0x00007fff8cc1f76f ReceiveNextEventCommon + 432
22 HIToolbox 0x00007fff8cc1f5af _BlockUntilNextEventMatchingListInModeWithFilter + 71
23 AppKit 0x00007fff8bf930ee _DPSNextEvent + 1067
24 AppKit 0x00007fff8c35f943 -[NSApplication _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 454
25 AppKit 0x00007fff8c1a4f9c NSCoreDragCGEventBlockingProc + 135
26 HIServices 0x00007fff866f867e SampleMouseAndKeyboard + 141
27 HIServices 0x00007fff866f8374 DragInApplication + 50
28 HIServices 0x00007fff866f7403 CoreDragStartDragging + 705
29 AppKit 0x00007fff8c1a2171 -[NSCoreDragManager _dragUntilMouseUp:accepted:] + 1010
30 AppKit 0x00007fff8c47fbbe _handleBeginDraggingSession + 97
31 CoreFoundation 0x00007fff9b4f7e37 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
32 CoreFoundation 0x00007fff9b4f7da7 __CFRunLoopDoObservers + 391
33 CoreFoundation 0x00007fff9b4e9a3a __CFRunLoopRun + 1178
34 CoreFoundation 0x00007fff9b4e9338 CFRunLoopRunSpecific + 296
35 HIToolbox 0x00007fff8cc1f935 RunCurrentEventLoopInMode + 235
36 HIToolbox 0x00007fff8cc1f76f ReceiveNextEventCommon + 432
37 HIToolbox 0x00007fff8cc1f5af _BlockUntilNextEventMatchingListInModeWithFilter + 71
38 AppKit 0x00007fff8bf930ee _DPSNextEvent + 1067
39 AppKit 0x00007fff8c35f943 -[NSApplication _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 454
40 AppKit 0x00007fff8bf88fc8 -[NSApplication run] + 682
41 AppKit 0x00007fff8bf0b520 NSApplicationMain + 1176
42 MY APP NAME 0x0000000100093602 main + 34
43 libdyld.dylib 0x00007fff99f425ad start + 1
Any ideas as to what can cause it? I don't see anything helpful in the debugger. Adding an exception breakpoint doesn't show me anything helpful either.