#Ultimate solution for this:
#http://askubuntu.com/questions/289858/disk-drive-for-dev-mapper-cryptswap-1-is-not-ready
(1) Run the following command:
sudo gedit /etc/fstab
(2) #### Then, using gedit, or vim, replace the following line:
/dev/mapper/cryptswap1 none swap sw 0 0
(3) # with a line, as follows, that adds , noauto to read:
/dev/mapper/cryptswap1 none swap sw, noauto 0 0
(4) # Then run the following command to edit your /etc/rc.local file:
sudo gedit /etc/rc.local
(5) # Immediately before the line that reads
exit 0
(6) # add these two lines:
sleep 5
swapon /dev/mapper/cryptswap1
(7) # Now,
I had the same issue. Eventually it turned out that the device in /etc/crypttab was wrong. The system was installed from a USB pen-drive. Because of this, during installation, the pen-drive was /dev/sda and the hard disc was /dev/sdb. The swap partition was hence written into /etc/crypttab as /dev/sdb6. After booting from the harddrive this became /dev/sda6 and the mapper could not find it any more. To fix this just correct the line in /etc/crypttab to the correct /dev/sd?? or the UUID of the swap partition. For example, if your swap is on /dev/sda4, you would change the following line: cryptswap1 UUID=9086ae06-9274-4627-adab-d3baae1e4ee3 /dev/urandom swap,cipher=aes-cbc-essiv:sha256
You would have a different UUID, of course. My UUID was 9086ae06-9274-4627-adab-d3baae1e4ee3. cryptswap1 /dev/sda6 /dev/urandom swap,cipher=aes-cbc-essiv:sha256
You would have a different /dev entry for your swap partition, of course. My /dev entry for my swap partition was /dev/sda6. I found it by installing gparted, running sudo gparted, and looking for a partition that had a type "unknown". I also looked in /etc/fstab for something like "# swap was on /dev/sda6 during installation", just to be sure. /dev/sda6 was the /dev entry. 