If you’re having frequent MySQL Workbench crashes in Mac OS X, check whether you don’t have some Subversion plugin installed, such as SCFinderPlugin or SCToolbarButton. Apparently they are outdated and do not work well in recent versions of OS X, causing certain other innocent applications to crash. Removing these plugins should fix the problem in affected apps, including Workbench.
See Bug #71119 or Bug #68080
To check whether this is your problem, look for a line similar to the following in the Mac OS X crashlogs generated for Workbench:
0xbe29000 - 0xbe2dff7 +org.tigris.scfinderplugin (169) <BBADB6CA-61AE-24D5-4E0A-EBCCAD3F0D92> /Library/Contextual Menu Items/SCFinderPlugin.plugin/Contents/MacOS/SCFinderPlugin
To uninstall that plugin, delete the following files/folders with sudo:
/Library/Contextual Menu Items/SCFinderPlugin.plugin /Library/Receipts/SCPlugin.pkg
The plugin seems to hook into some System framework (probably Finder or NSWorkspace related) and causes some Cocoa API calls to become messed up and any application that use these same APIs will become unstable.