A user at work reported that ChemDraw suddenly started segfault-ing (crashing) on startup on his Mac. He’d opened a support ticket with CambridgeSoft and tried their suggestions, basically deleting every file associated with ChemDraw and reinstalling, which didn’t correct the problem.

I suspected that this was an issue with ChemDraw 12.0.2 (I’m using 12.0.1 and so are other CMLD members for the research lab I support). I suggested that he create a new user on his Mac and see if ChemDraw works correctly. I reasoned that ChemDraw was upgraded sometime in the past, and that there may have been some user preferences causing issues after upgrading, or some preferences settings were corrupted.

If a new user was able to use ChemDraw, then this would indicate that the installation is valid and working, and the issue is with the user’s preferences. If ChemDraw didn’t work, then the issue is probably with the installation, and we would need to install the application, and hunt down any remnants of the installation that may be in /Library or /System and then reinstall 12.0.1 to see if that would resolve the problem.
In this case, ChemDraw worked for the new user, thus indicating that the issue was not with the installation, but with the user’s setting. Deleting any files whose name started with com.cambridgesoft files in

/Users/[Your User Name]/Library/Preferences

resolved the problem.