As was working on developing a Firefox extension, I wanted to make a special user profile for development in Firefox. Many tutorials advise you to type the following into terminal to get in the user profile screen.
However, that wasn’t working for me. I couldn’t easily find a fix for it on Google, so here is an overview of other methods to get into the user profile settings for different Mac OS X versions (source), hope it can help some fellow Googlers.
On Mac OS Snow Leopard (10.6) and newer, type this in the terminal:
On Mac OS Leopard (10.5) and older, type this in the terminal (on one line):
The last one worked for me. So if you are having problems with switching between users in Firefox on Mac OS X, try the code above. Let me know, if you got it to work!