Windows has a feature called Dynamic Disks, which makes it ignore the DOS partition table and manage partitions its own ways. gparted is supposed to detect that, and warn the user that it can’t deal with that. The solution is to reboot in Windows, switch the partition back to “Basic disks”, and then proceed with installing Debian (or Ubuntu).
However, a student of mine had an interesting experience because gparted did not detect the dynamic disk stuff and did not warn about it, so the student went ahead with installing Debian squeeze. After reboot in Windows, Windows sees the partition as “invalid”. The same happens with Ubuntu 11.04 (not really surprising).
I’m surprised I did not find much information about that issue. Does someone has more info ?
The student was using two disks in his laptop, and only the second one (not the one used to boot windows) was using “dynamic disks”.