Hi,

My experience is that this happens when I have a crash, so it sounds as if you are not getting a clean exit out of FF?

Make sure that you clear the browser cache, java cache, history, unwanted cookies and all that, then go for what MoonWolf has suggested.

Does this happen when you run FF OFFLINE? please try it. If it does then disable your firewall and try it, and disable your AV and try it.

This is a wild shot but if you have a large volume of temporary, cache, history and whatever files, and your AV is set to scan on file close, this could be the problem?

just a thought