If the sync plugin (that uses a WeaveCrypto.so component) isn't working properly then you have to uninstall it.

You can also check the log file in the weave/logs folder or delete that full folder or try to uninstall and reinstall the Firefox Sync extension.

See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

I have uninstalled and then installed the sync plugin. I have uninstalled and the installed firefox. I have run firefox -profile-manager and created a new profile.

Thank you for the info regarding the .so and and log file.

When firefox crashes nothing is appended to the log file. So I started looking at the access times on WeaveCrypto.so. When firefox successfully starts in normal mode, the access time on the .so in the x86_64 directory is set. However, when firefox crashes the access time does not get set (ie. WeaveCrypto.so is never accessed.)

I am still confident that this has something to do the extension Firefox Sync 1.5.1 since if it is uninstalled or disabled everything works perfectly. On a side note, this problem is not new to this computer it has occurred with all versions of the extension starting at (I think) 1.3.

It does not appear to be an extension conflict. The crashes still occur if I disable every extension except Firefox Sync.

Updating to 3.6.13 seems to have fixed the problem.

What is proper way to mark as solved?