みんな既知だと思うのですが、仕事用と個人用両方でXcode12で、
launchからプロジェクトを起動すると、異常終了します。。
個人的にはWindowタブバーを開いていると発生する確率が高くなるような気がします。
####Apple Forum
https://developer.apple.com/forums/thread/669767
####Xcodeの問題レポート
error
Process:               Xcode [7830]
Path:                  /Applications/Xcode.app/Contents/MacOS/Xcode
Identifier:            Xcode
Version:               12.4 (17801)
Build Info:            IDEFrameworks-17801000000000000~7 (12D4e)
App Item ID:           497799835
App External ID:       839994694
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           Xcode [7830]
User ID:               501

Date/Time:             2021-04-10 05:21:46.217 +0900
OS Version:            Mac OS X 10.15.7 (19H2)
Report Version:        12
Bridge OS Version:     4.6 (17P6610)
Anonymous UUID:        FD892C39-8E2D-2133-2B67-562223514F4F

Sleep/Wake UUID:       A5FA3011-9375-406F-824F-1751C2E366E1

Time Awake Since Boot: 28000 seconds
Time Since Wake:       1800 seconds

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: 12D4e
ASSERTION FAILURE in /Library/Caches/com.apple.xbs/Sources/IDEFrameworks/IDEFrameworks-17801/IDEKit/Workspace/IDEWorkspaceDocument.m:3270
Details:  (tabController) should not be nil.
Object:   <IDEWorkspaceDocument: 0x7f82266957f0>
Method:   -commitStateToDictionary:
Thread:   <NSThread: 0x7f821ac1c080>{number = 1, name = main}
Open FDs: 39/7168
Hints:   
 
Backtrace:
  0   -[IDEAssertionHandler handleFailureInMethod:object:fileName:lineNumber:assertionSignature:messageFormat:arguments:] (in IDEKit)
  1   _DVTAssertionHandler (in DVTFoundation)
  2   _DVTAssertionFailureHandler (in DVTFoundation)
  3   -[IDEWorkspaceDocument commitStateToDictionary:] (in IDEKit)
  4   -[DVTStateToken _copyStatefulObjectState] (in DVTFoundation)
  5   -[DVTStateToken pushStateToRepositoryAndReturnError:] (in DVTFoundation)
  6   -[DVTStateRepository _updateStateIfNeeded] (in DVTFoundation)
  7   -[DVTStateRepository collectStateFromRegisteredObjects] (in DVTFoundation)
  8   -[IDEWorkspaceDocument writeStateData] (in IDEKit)
  9   __28-[IDEWorkspaceDocument init]_block_invoke (in IDEKit)
 10   -[DVTDelayedInvocation runBlock:] (in DVTFoundation)
 11   __NSFireDelayedPerform (in Foundation)
 12   __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ (in CoreFoundation)
 13   __CFRunLoopDoTimer (in CoreFoundation)
 14   __CFRunLoopDoTimers (in CoreFoundation)
 15   __CFRunLoopRun (in CoreFoundation)
 16   CFRunLoopRunSpecific (in CoreFoundation)
 17   RunCurrentEventLoopInMode (in HIToolbox)
 18   ReceiveNextEventCommon (in HIToolbox)
 19   _BlockUntilNextEventMatchingListInModeWithFilter (in HIToolbox)
 20   _DPSNextEvent (in AppKit)
 21   -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] (in AppKit)
 22   -[DVTApplication nextEventMatchingMask:untilDate:inMode:dequeue:] (in DVTKit)
 23   -[NSApplication run] (in AppKit)
 24   NSApplicationMain (in AppKit)
 25   start (in libdyld.dylib)
 
abort() called

Application Specific Signatures:
((tabController)) != nil

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib        	0x00007fff68dba33a __pthread_kill + 10
1   libsystem_pthread.dylib       	0x00007fff68e76e60 pthread_kill + 430
2   libsystem_c.dylib             	0x00007fff68d41808 abort + 120
3   com.apple.dt.IDEKit           	0x000000010e3fe7d2 +[IDEAssertionHandler _handleAssertionWithLogString:assertionSignature:assertionReason:extraBacktrace:] + 1275
4   com.apple.dt.IDEKit           	0x000000010e3fecd8 -[IDEAssertionHandler handleFailureInMethod:object:fileName:lineNumber:assertionSignature:messageFormat:arguments:] + 1068
5   com.apple.dt.DVTFoundation    	0x000000010c84628b _DVTAssertionHandler + 476
6   com.apple.dt.DVTFoundation    	0x000000010c84648e _DVTAssertionFailureHandler + 306
7   com.apple.dt.IDEKit           	0x000000010e319cba -[IDEWorkspaceDocument commitStateToDictionary:] + 2146
8   com.apple.dt.DVTFoundation    	0x000000010c6e48a1 -[DVTStateToken _copyStatefulObjectState] + 143
9   com.apple.dt.DVTFoundation    	0x000000010c6e4aba -[DVTStateToken pushStateToRepositoryAndReturnError:] + 77
10  com.apple.dt.DVTFoundation    	0x000000010c7802d7 -[DVTStateRepository _updateStateIfNeeded] + 352
11  com.apple.dt.DVTFoundation    	0x000000010c7812a6 -[DVTStateRepository collectStateFromRegisteredObjects] + 79
12  com.apple.dt.IDEKit           	0x000000010e31743a -[IDEWorkspaceDocument writeStateData] + 511
13  com.apple.dt.IDEKit           	0x000000010e303729 __28-[IDEWorkspaceDocument init]_block_invoke + 180
14  com.apple.dt.DVTFoundation    	0x000000010c608dfd -[DVTDelayedInvocation runBlock:] + 860
15  com.apple.Foundation          	0x00007fff312906e2 __NSFireDelayedPerform + 415
16  com.apple.CoreFoundation      	0x00007fff2ebd67f9 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
17  com.apple.CoreFoundation      	0x00007fff2ebd635f __CFRunLoopDoTimer + 859
18  com.apple.CoreFoundation      	0x00007fff2ebd5e47 __CFRunLoopDoTimers + 322
19  com.apple.CoreFoundation      	0x00007fff2ebbabea __CFRunLoopRun + 1871
20  com.apple.CoreFoundation      	0x00007fff2ebb9e3e CFRunLoopRunSpecific + 462
21  com.apple.HIToolbox           	0x00007fff2d7e6abd RunCurrentEventLoopInMode + 292
22  com.apple.HIToolbox           	0x00007fff2d7e67d5 ReceiveNextEventCommon + 584
23  com.apple.HIToolbox           	0x00007fff2d7e6579 _BlockUntilNextEventMatchingListInModeWithFilter + 64
24  com.apple.AppKit              	0x00007fff2be2c039 _DPSNextEvent + 883
25  com.apple.AppKit              	0x00007fff2be2a880 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 1352
26  com.apple.dt.DVTKit           	0x000000010cf12d07 -[DVTApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 421
27  com.apple.AppKit              	0x00007fff2be1c58e -[NSApplication run] + 658
28  com.apple.AppKit              	0x00007fff2bdee396 NSApplicationMain + 777
29  libdyld.dylib                 	0x00007fff68c72cc9 start + 1
〜以下省略〜