I partitioned my new 80Gb HD into four equal partitions, each 20Gb. I installed Mandrake Linux 8.1 on the second partition (20Gb), with the third and fourth set aside for Windows programs and documents respectively. However, once I installed Mandrake and configured it, and then went BACK to windows the other two come up as 'healthy' but as 'unknown partitions' in Disk Management in XP (the c: partition is untouched). Windows still recognises them as NTFS file systems, but does not allocate them a drive letter. The only thing you can do with them is delete them, apparently. I thought this might be because it was on the same physical drive, so I tried removing the Linux partition from the 80Gig drive, making that three partitions and moving the linux install to it's own dedidcated 8Gig hard drive. It did the SAME THING to my new documents and programs partitions (nothing lost fortunately, I'm a back-up fiend). I have also tried installing Mandrake to it's own drive, waiting for the install to screw up my two partitions on Disk0/hda and repartitioning them in Disk Management in XP. I then went and played about in Linux (actually, I just configured my modem), shut down, and rebooted XP. Again, the same thing, two partitions rendered useless, even when they are on totally different physical drives. This is wierd and I don't understand. Can anyone help? Cheers, Steve

2 partition deleted without you deleting them? How do you know they are deleted? Did you try booting linux? What do you have as bootloader? LILO or Grub? What does grub/lilo/linux say when you try to boot? Give the full message please. Also, use a more reliable disk tool from now on, the "fdisk" and "cfdisk" included with most distros are good.

Not deleted, no. Please read the second paragraph. I have tried mainly Lilo, but I'm fairly sure grub has the same effect. Why would I need a more reliable disk tool?

I got a similar problem. I've got three different drives on my xp system. All drives are NTFS drives and all was fine till i installed system commander 7. Now my C: drive works fine but my other 2 drives come up as unkown partition (Healthy) in disk manager. The 2 drives are unusable and dont show up in windows explorer. All i can do to the drives is delete them. I have a lot of data in there and no backups. Can anyone help?