Comment # 2 on bug 905653 from Neil Rickert

I'm just a user.  But I have seen this message.

In my case it was caused by a corrupt partition table that had some of the
format of a GPT partition table and some of the format of a traditional legacy
partition table.  The installer uses "parted" for partitioning, and it does not
want to touch this partition table.

Assuming that your problem is the same, there are two options:

(1) convert to a GPT partition table.  Running the command "gdisk /dev/sda"
will probably accomplish that.

(2) convert to a legacy MBR partition table.  The command "fixparts /dev/sda"
should accomplish that.

Given that you have Windows installed, probably for UEFI booting, I would
advise (1).

A problem.  As far as I know, neither "gdisk" nor "fixparts" is on the install
DVD.  So use live media.  If you don't currently have, then download the live
Rescue CD image.  That should already have "gdisk", but it won't have
"fixparts".  So you will need to install "fixparts" before you can use it.  If
using the rescue image as a CD, I think that installs to RAM, so will disappear
on reboot.  If using the rescue image on a USB, it should save the installed
"fixparts" to persistant storage on the USB.

And a suggestion to the developers -- please include "fixparts" on the live
rescue image for future releases.