I am hitting the error at line 1133 of nsIdentityChecking.cpp a lot when running trunk in debug mode. I believe this is because the thumbnail background stuff running in the plugin-container process is using this method when it should only be used from the main process (as described in the comment above the error). I noticed this at first with experimental OMTC stuff, but it reproduces with equal frequency without OMTC.

I tried to get a stack trace but can no longer reproduce (with or without OMTC). But that seems to be because plugin-container is not starting up, so I'm not sure if there is some magic involved in how often the page thumbnailer runs or something. If it crashes again I'll post a stack trace.

(In reply to Nick Cameron [:nrc] from comment #1) > I'm not sure if there is some magic involved in how often the page > thumbnailer runs or something. If it crashes again I'll post a stack trace. In general, that process will only start when (a) you open about:newtab and (b) some thumbnails on that page are > 2 days old. And once it's started it will terminate if unused for ~60 (IIRC) seconds. The easiest way to force it to run is to delete all files from the 'thumbnails' directory in your profile then open about:newtab.