Yesterday afternoon I found I couldn’t run QGIS at all – it kept crashing on startup, whenever it got to the splash page “loading plugins” bit. I tried restarting without plugins running (/Applications/QGIS.app/Contents/MacOS/QGIS –noplugins) but it would still crash when I went to the “Manage Plugins …” menu option, so no chance of turning them off.
Running QGIS as the guest user worked fine – so I figured it probably wasn’t a problem with bad frameworks, the system or the app itself. Using AppCleaner to search for QGIS-related directories came up with a few things but deleting ’em didn’t help (it missed the .qgis hidden directory in the user folder).
So, to do a clean install or to remove potentially troublesome data (no need to delete QGIS itself), open a terminal session and enter:
rm ~/Library/Saved\ Application\ State/org.qgis.*
rm -r ~/.qgis/
… and that should do the trick!
* in the past few days I installed qgsAffine and multiqml but not sure that’s the actual problem.