Comment 8 for bug 107152

You have the following partitions already, in order:

  * 40GB primary NTFS partition
  * 19GB primary partition marked "unknown"
  * 1GB logical Linux swap partition
  * 18GB logical Linux ext3 partition
  * a small amount (7MB) of free space at the end of the disk

The installation needs a minimum of two new partitions, at least one of which will have to be logical (you can only have four primary partitions, and one of those slots is used up by the extended partition containing the logical partitions).

We can't resize the NTFS partition. All logical partitions must be in an extended partition; you can only have one extended partition; you already have an extended partition containing those two logical partitions; that extended partition is at the end of the disk. Putting all this together, you can see that there's no way to put a logical partition between the NTFS partition and that "unknown" partition.

We can't resize the "unknown" partition because we don't know what it is. I suspect it's some kind of recovery partition?

We can't resize the Linux swap partition because it's too small; an Ubuntu installation won't fit into 1GB.

That leaves the Linux ext3 partition. For some reason, partman couldn't figure out how to resize it. Since you said you were using Ubuntu 6.10 for your second test, I strongly suspect that this was bug 59620, and I'm going to mark this as a duplicate of that. If you find that you can still reproduce this with Ubuntu 8.04 beta once that's released, then please file a new bug with the logs I requested here.

It may also be that you were originally running into bug 134950, which will be fixed in the 8.04 beta. Autopartitioning options are strongly dependent on the state of the disk, and so I won't be able to say for sure without logs.