I'm on a G3 iMac. On a "new to me" G5 iMac; I moved Firefox 3.5.6 from the G3. When I open Firefox the G5 says "quit Firefox, Firefox is open, can't have >1 copy open". Firefox isn't open, only finder. What to do?
There was a Firefox 3.6 installed on the G5 by a friend, but my profile was not installed. To be sure of compatibility, I trashed the Firefox 3.6 and copiedFirefox 3.5.6 from the G3 (where it runs fine) to the G5. I also copied my profile. On the G5, I had moved the Firefox icon onto the dock. I checked finder and there is only one application of Firefox on the G5 hard drive. Just now I started the G5; when I had finder, I clicked on the Firefox application on the dock. A message opened saying: Close Firefox. A copy of Firefox is already open. Only one copy of Firefox can be open at a time.
Opaite Mbohovái (2)
Wild guess: if you copied your profile while Firefox was running, there might be a lock file in your profile preventing Firefox from starting. Check out this article for more information: Profile in use - MozillaZine Knowledge Base.
Did you copy profiles.ini as well or registered the copied profile by creating a new profile and set the location to that copied profile?