Unsafe swap space detected

Try to boot via "Try Ubuntu" instead of "Install Ubuntu" and run the command:

sudo swapoff --all

From the terminal. (ctrl+alt+t)

Then run the Install Ubuntu from the desktop. The error should stop appearing.

See also this related Lubuntu/ubuntu bug report

Len's solution of running sudo swapoff -all is possible without booting via "Try Ubuntu".

When you get the error, use CTRL-ALT-F1 to get to a terminal and run the command there.

Use CTRL-ALT-F7 to return to the graphical environment when you're done.

It worked for me. I did so after going back to the language selection screen, but it may work from the partition manager stage. I would expect the check is only being done at the moment one attempts to change a partition.

I had the same problem, there's definitely something wrong with the installer (I was trying to set up 14.04 with encrypted partitions on different drives, with / on my small SSD and /home /usr /tmp /var and swap on my HDD). But I played around with it, restarted the installer/rebooted a number of times, and here's how you work around it:

Set up all your actual partitions, including your encrypted containers. I believe it necessary to include an encrypted partition for swap, so make sure to make one of suitable size for it.

Once you have them all set up, THEN, and only then pin them to actual mount points. I started with swap and then moved on to /home and so on.