Xcode Error Report Xcode quit unexpectedly

Question

After updating Xcode to 11.2.1 I am unable to open my project. Everytime I try to open it Xcode crashes and I get the following error.

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: 11B500
ASSERTION FAILURE in /Library/Caches/com.apple.xbs/Sources/IDEFrameworks/IDEFrameworks-15526.1/IDEKit/Workspace/IDEWorkspaceDocument.m:3429
Details:  selection failed. window:<IDEWorkspaceWindow: 0x7f95c63dfb70> currentlySelectedTabbedWindow:<IDEWorkspaceWindow: 0x7f95c7c51350>
Object:   <IDEWorkspaceDocument: 0x7f95c60d7580>
Method:   -_restoreSelectedTabsByIdentifierFromStateSaving:
Thread:   <NSThread: 0x7f95c0703790>{number = 1, name = main}

Answer 1

It seems that Xcode cannot restore the tabs / files you have opened the last time see Method: -_restoreSelectedTabsByIdentifierFromStateSaving:.

The latest ui state including opened files, curent target etc. is stored in the UserInterfaceState.xcusertate. You can find the file in your Xcode project folder under:

/<your_project_path>/<your_project_name>.xcodeproj/project.xcworkspace/xcuserdata/<username>.xcuserdatad/UserInterfaceState.xcuserstate

Just remove the file e.g. via rm and Xcode shall work again.

Answer 2

Open project folder show package contents from .xcworkspace or .xcodeproj You will see 2 folders xcshareddata and xcuserdata Please remove xcuserdata folder Try to open application Xcode will work properly