Comment 30 for bug 898336

(In reply to comment #5)
> (In reply to comment #4)
> > Are you sure it was nautilus and Thunar was not involved here?
> You are right on the spot - Though I was 100% sure to once have configured
> nautilus as my preferred "File Manager", I currently have Thunar :)

If you are using Xfce you can use exo-preferred-applications to select your favorite file manager. Not all GNOME apps honor this setting though and I don't know where to set the default file manager in GNOME 3.x

> Also, as I don't actually know what thumbler does, I am not sure if it's
> actually launching totem on a particular video which causes the segfaults, but
> browsing a folder of videos - thumbnail creation?

Bingo!

You can remove /usr/lib*/tumbler-1/plugins/tumbler-gst-thumbnailer.so if the crashes continue.