I think I am having a similar problem. Please see the following forum discussion: http://ubuntuforums.org/showthread.php?t=343570&highlight=swap+file+fails
-- After running mkswap, swap space is discarded, system fails to hibernate (invalid swap signature) https://launchpad.net/bugs/66637 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
