You might ask yourself: Where are the FireFox extensions and plugin folders located on OSX Mac?
Of perhaps you’re asking yourself: How to I get to use my FireFox within it crashing?
So, it’s best to not delete any files right away. Just move them to a temp folder or keep them in the Trash bin.
Verify these folders:
Get your Profile folder. Open FireFox, got to Help->Troubleshooting Information
Note: Some extensions create subfolders of their own with data and logs which might need to be cleaned manually.
Be sure to Close / Restart your browser after making changes if you want to test the results.
Also filed under: Fix Flash Crashing, Flash Crashes on YouTube, Quick Flash Crashing Fix