Thunderbird app won't open

No 'System Restore' app in OS X? That's puzzling. Same for the new Snow Leopard?
I could use it.

I installed the mail app Thunderbird in OS X and then dropped a copy of my Tbird "profile" folder from WinXP into it. Since then the Tbird app won't open- I get the message, 'already a copy of Tbird open and only 1 can run' (even right after boot). So I uninstalled Tbird with AppCleaner1.2.2, and then re- download & install of Tbird. Same prob-- even after boot Tbird won't open because of already running!

Ideas anyone?

Who knows what that XP profile folder did when you first tried to run it. That was a pretty gutsy move. Too bad it didn't work out. Try downloading and installing EasyFind. Then use AppCleaner again. Then search with EasyFind for hidden and System T-Bird files. Nuke'em. Then reinstall T-Bird and see if it works.

Try using the included Profile Manager to migrate your profile. More here.

Thanks guys, all bettter now.
STEPHEN CHU . com: Migrate Thunderbird mailboxes from Windows to Mac
This was the article that got me to migrate across OSs. Tbird is one mail app that files in universal format and works on 3 OSs, Mac, Linux and the other.

EasyFind removed some files on the first quick use, but left a Tbird folder in profiles... but after deleted those it did fully uninstall and re-install cleanly, opened & ran fine.
This time I deleted the CONTENTS of the xgrxgr5d.default folder instead deleting the whole folder. I replaced with the contents of the .default folder of my Tbird in XP.
It's golden-- all my accounts set are up, and my custom folders are there to use.

The experience highlights a major advantage of Windows (but also of Mac).
My OS X was able to read the WinXP portion of my MBP hard drive and easily copy that profile folder.
Windows System Restore is elegant and efficient and Mac doesn't have it. Time Machine is a great name-- which would better name the function of what Windows System Restore does.

Thanks for the Profile Manager pages from Mozilla. With "the migration of the Tbird" complete, plus I got Outlook migrated to iCal... my comfort level is high and I can set my boot camp default to Mac.