Xcode 9 crashes on launch

I have installed the beta on an iMac (2 years old) as well as laptop, both using Sierra. Runs fine on the laptop. But on the iMac, I launched it successfully, tried to add a Github account before opening any project, and it crashed. Subsequently, unable to launch Xcode beta at all - starts up and crashes immediately. Reinstallation did not change this.


Are there configuration files that I may have corrupted by trying to set up Git account before doing anything else? Files that I should simply erase and then reinstall the beta?


Complication is that I am using version 8.3.3 on real project (which is on GitHub) and would prefer not to mess up settings in that environment.


Thanks.

I am also having XCode 9 Betacrash repeatedly while working with GitHub. I have also just set up GitHUb in the XCode beta for the first time. So far, I can proceed - just a little bit at a time. Have to keep Force Quitting and re-starting Xcode.

Xcode 9 crashes on launch
 
 
Q