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
Up vote post of Gursimransarao Down vote post of Gursimransarao
12k views
Posted by
Gursimransarao
Reply

  • Typing "defaults write com.apple.dt.Xcode DVTDisableMainThreadChecker 1" in terminal worked for me. And then opening xcode, asked to install additional components. Thanks

    —
    negiruh

  • 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?

    —
    gregneff

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

    —
    gregneff

Replies

Same problem with you. 😨😨😨😨😨😨😨
Posted by
zhangxi
Post not yet marked as solved Up vote reply of zhangxi Down vote reply of zhangxi
Add a Comment
Same issue

Posted by
JRobinson2
Up vote reply of JRobinson2 Down vote reply of JRobinson2
Add a Comment
Same issue, I'm struck I couldn't proceed with my work. It's frustrating.
Posted by
BK1982
Up vote reply of BK1982 Down vote reply of BK1982
Add a Comment
Can we please get a moderator to respond to this issue. We are totally blocked on any work related to Big Sur
Posted by
leyva62
Up vote reply of leyva62 Down vote reply of leyva62
Add a Comment
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
Posted by
ganeshbelki
Post not yet marked as solved Up vote reply of ganeshbelki Down vote reply of ganeshbelki
Add a Comment
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 by
yanincontreras
Post not yet marked as solved Up vote reply of yanincontreras Down vote reply of yanincontreras
Add a Comment
Hello, same issue here after installing Mac OS BIG sure.
Posted by
AntoineLL
Post not yet marked as solved Up vote reply of AntoineLL Down vote reply of AntoineLL
Add a Comment
"""defaults write com.apple.dt.Xcode DVTDisableMainThreadChecker 1"""

Work with me
Posted by
Gang.Liu
Post not yet marked as solved Up vote reply of Gang.Liu Down vote reply of Gang.Liu
Add a Comment

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

Posted by
cyeh1234
Post not yet marked as solved Up vote reply of cyeh1234 Down vote reply of cyeh1234
Add a Comment

I had the same issue where I have multiple versions of Xcode to practice along with different Xcode books. Xcode 10.0, 11.3, and 12 all worked fine after downloading. This 10.2.1 version kept giving me the crash error and I needed this version to run some code from a different book. Tried replacing the libMainThreadChecker.dylib from 10.0 and 11.3 and it didn't work for me. The file from Xcode 12 worked so now Xcode 10.2.1 works for me. Hopefully this helps anyone with similar issue.

I am very worry personally in running any terminal commands in case fixing the 10.2.1 would break my other Xcode versions.

Would suggest to make a backup with Time Machine or Super Duper before making changes like this.

Posted by
ssan
Up vote reply of ssan Down vote reply of ssan
Add a Comment