User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8b4) Gecko/20050729 Firefox/1.0+ Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8b4) Gecko/20050729 Firefox/1.0+ I've already reported an earlier crash that I've been getting with the nightlies (Bug #302355) and this is another one that I've seen quite often - about one every two or three hours. The stack seems to be JS-related, also. These crashes started occurring around the same time as Bug #302355's crashes started (maybe about a week or so by now?). The problem is I can't seem to find a consistently reproducible testcase. If I can, I'll post an update. Reproducible: Sometimes

Oh, and this occurs with a brand new profile, too.

Arg. I shouldn't have entered "background" in the name of this bug - crashes occur in the backgound as well as when Firefox is active. Sorry!

bug 293902 among others relates to crashing in js_FinalizeObject actually both this and your bug 302355 are crashes under js_FinalizeObject, i'd presume they're the same crash.

Neil, are you still seeing this crash? Do you have any talkback incident ids?