This all seems to come from the kernel soft lockup triggered by usplash on AMD64. See bug #60053. Disabling usplash solved the problem, that was not directly related to gconf / evolution.
-- Evolution losts the accounts settings across reboot https://launchpad.net/bugs/60443 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
