Comment 4 for bug 798285

Somehow, all my messing around (see previous comment) had broken my Windows 7 installation so that even the recovery tools on the Windows 7 cd could no longer fix it. Thankfully this was a fresh install, so I decided to do some more testing.

I eventually used Disk Utility from an Ubuntu live-cd to create a new partition table, then reinstalled Windows 7 on 50% of the drive. The Ubuntu installer then correctly detected the Windows installation and was able to install on the empty remaining 50%. The grub menu was also correctly configured to dual-boot.

I think the bug was caused by the remaining GUID Partition Table from OS X Lion. It appears the Windows installer does not correctly create a new table when you use it to delete all current partitions and create new ones. Windows was able to install and boot fine, but Ubuntu's installer got confused by the remaining GPT stuff. I don't know enough about this to really know. Creating a new MS-DOS partition table apparently created a fresh slate to work on.

This is probably a bit of an edge case, since it would involve three OS's in a specific sequence, but it may be worth looking into because of the potential for data loss. A clueless user would easily wipe his entire disk, and even my careful (I thought) attempts to troubleshoot ruined the Windows partition.

I guess the following steps would reproduce this bug:
1. Create GPT partition table with OS X.
2. Boot Windows 7 installer and select manual partitioning
3. Remove all partitions via Windows installer.
4. Create new partition taking about 50% of the drive. Windows automatically creates a small (100MB) recovery partition too.
5. Install Windows.
6. Boot from Ubuntu cd.
7. Bug: Ubuntu installer can't detect Windows installation, and offers to overwrite the whole disk. Manual partitioning also shows the entire disk to be empty. Disk Utility or Gparted do show some partitions, but incorrectly, and any actions on the disk fail, potentially damaging the actual partitions beyond easy repair.