While booting Ubuntu 12.04,
the disk drive for /dev/mapper/cryptswap1 is not ready yet or not present is showing. What is this? Is this is an error?
This error message indicates that the the system was unable to use its encrypted swap partition. If you don't believe you have an encrypted swap partition (or encrypted swap file), please comment and edit your question with details.
Not being able to use swap may cause slowdown, especially if your machine doesn't have much RAM installed.
Assuming the system is booting, you should be able to fix the problem without too much hassle.
If this is happening when you boot the CD/DVD or USB flash drive to install Ubuntu, then assuming installation is still working, it can be ignored. Your installed system might or might not have the same problem once created--if it does, the problem can be addressed in the installed system.
If this is happening on a system that is installed on your hard disk, then your system might still run okay, but it's a good idea to fix it--if you have a swap partition (or swap file), you may as well use it.
Most Ubuntu systems with swap have a swap partition. Assuming that is the case, the technique described in this blog post may help:
Here's a summary, with some additional information that may be helpful for novices, and in my own words. I suggest taking a look at that post as well though (assuming it remains accessible), as it contains some examples and other information that I've left out for brevity.
Source: http://punygeek.blogspot.com/2012/10/ubuntu-1204-how-to-solve-disk-drive-for.html (on http://punygeek.blogspot.com/) by Litmus / Puny Geek. Some commands are copied; prose is not copied, but often expresses the same ideas.
Finally, note that this might be a bug. (I believe multiple factors could cause this problem, only some of which are bugs.) In particular, it resembles Launchpad Bug #1153661. If you believe that's your situation, you might want to subscribe to that, mark yourself affected (with the green "This bug affects..." link at the top of the page), and if you have any additional information to provide, comment with it.
protected by Community♦ Nov 14 '13 at 18:27
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