If you’ve read and followed my advice on re-creating the swap partition after failed hibernation, there is one caveat I discovered: after recreating, the swap partition is not automatically mounted. This can result in sever system instability and programs crashing very quickly due to their inability to allocate memory. To verify that your swap partition is mounted, fire up a console and execute the free command (thank you my Linux guru friend). If on the last line is says Swap: 0 0 0, you have a problem. Fortunately remounting the swap partition does not require reboot, just execute (from a console): sudo swapon -a. Also, check after the next reboot if the swap partition got mounted (just to be sure).

Also, if you’re short of disk space and want to follow my advice on deleting crash dumps, be sure to also check under /var/crash, which is an alternative place to store crash dumps as I discovered. You need root privileges to delete files from here, so if you want to remove them, do a sudo rm /var/crash/*.

I was trying to get Ubuntu (6.10) to hibernate, without much success (remember, I’m a Linux newbie). One of the side effects of the experiment was that Ubuntu did not recognize my swap partition any more (probably because during the hibernation-attempt it was overwritten with some random data from memory).

If you find yourself in a similar situation, you can run the Gnome Partition Editor, by typing in a console sudo gparted or pressing Alt-F2 and typing gksudo gparted. You should see an unknown type partition in the list. Delete it and (re)create a partition with type linux-swap in the free space. Now reboot your computer. This should solve the problem.

Warning! Using the partition editor, you can seriously damage your computer and lose data! Only use it if you know what you are doing!

Update: please read the followup on this advice.