xcode crashes after mac os Big sur update

I downloaded new mac os big sur developer beta and Xcode has started crashing.
when I open Xcode, it says xcode quit unexpectedly while using the libMainThreadChecker.dylib plug-in.
my Xcode version is 10.3
and it was working perfectly fine on catalina
  • Typing "defaults write com.apple.dt.Xcode DVTDisableMainThreadChecker 1" in terminal worked for me. And then opening xcode, asked to install additional components. Thanks

  • this particular terminal note fixed my original issue. And as noted above, was prompted to install additional components. When agreeing, I get a message box which says "An unknown error occurred. See the install log for more details" when i click try again it attempts for split second and then this message comes right back up. Anyone know a work around here?

  • aaaand the cause was xcode was still updating...

Answers

Same problem with you. 😨😨😨😨😨😨😨
Same issue

Same issue, I'm struck I couldn't proceed with my work. It's frustrating.
Can we please get a moderator to respond to this issue. We are totally blocked on any work related to Big Sur
Run the following command in Terminal: defaults write com.apple.dt.Xcode DVTDisableMainThreadChecker 1, then deselect Main Thread Checker in the Diagnostic tab of the Run and Test actions for each scheme in your project.

More info: https://developer.apple.com/documentation/macos-release-notes/macos-big-sur-11-beta-release-notes
You can fix this by replacing the 'libMainThreadChecker.dylib' file with the one in the working Xcode.

Go to this path on both the Xcode's you have, beta and 10.3: /Xcode.app/Contents/Developer/usr/lib and copy the file from the Xcode that is working to the one that is crashing.
Hello, same issue here after installing Mac OS BIG sure.
"""defaults write com.apple.dt.Xcode DVTDisableMainThreadChecker 1"""

Work with me

It works, thanks

You can fix this by replacing the 'libMainThreadChecker.dylib' file with the one in the working Xcode.

Go to this path on both the Xcode's you have, beta and 10.3: /Xcode.app/Contents/Developer/usr/lib and copy the file from the Xcode that is working to the one that is crashing.

Posted 8 months ago by yanincontreras