Installer won't detect existing oS or partition table.

[Paul D]

I was trying to install a newer version of Ubuntu, 10.04/10.10. When I use live CD, it won't detect any existing OS or partitions. Same with Alternative installer: It won't see any partitions, just my hard drive. There have been many questions about this but none of them seemed to help.

I wanted to have a new version of Ubuntu but preferably without having to re-install windows as well. I really don't know where the partition table went. The installers just don;t see anything. Both operating systems work fine, GRUB is always working correctly.

The problem is described in more detail in question #159921. I hope this helps.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Gaurav Butola (gauravbutola)]

I am having this issue with 11.10 . Ubiquity doesn't detect the existing windows 7 partition and when I choose to manually partition the disk, I can't see any partition there.
When I log into the live system and open Disk Utility, It shows my HDD partitions fine but Ubiquity for some reason is unable to detect them.
Can't install 11.10 'cause of this issue :(

[Martijn Heemels (yggdrasil)]

This bug still persists with Ubuntu 12.04 Desktop.

I installed Windows 7 SP1 64-bit on a harddisk scavenged from a Mac today. i deleted all current partitions and split the drive in two partitions in the Windows installer. Windows automatically created a small third partition at the beginning of the drive, which I assume is meant for the GPT. I installed Windows on one half of the drive, and left the other half unpartitioned.

Then, I tried installing Ubuntu 12.04 from the Desktop live-cd. At the partitioning step the installed mentioned that it didn't detect another OS on the computer so to avoid the 'wipe all' option I opted to partition manually. No partitions were visible in the tool, so I exited the installer.

Both Disk Utility and Gparted show some partitions. Only Disk Utility shows the small 100MB boot partition, Gparted does not.
Both tools recognize the drive has a GUID partition table.

Both tools are unable to create a new partition in the empty space, but Gparted spits out the following warning:

====================================================
Error creating partition: helper exited with exit code 1: In part_add_partition: device_file=/dev/sda, start=57777586176, size=62256537600, type=0x83
Entering MS-DOS parser (offset=0, size=120034123776)
MSDOS_MAGIC found
looking at part 0 (offset 1048576, size 104857600, type 0x07)
new part entry
looking at part 1 (offset 105906176, size 57671680000, type 0x07)
new part entry
looking at part 2 (offset 0, size 0, type 0x00)
new part entry
looking at part 3 (offset 0, size 0, type 0x00)
new part entry
Exiting MS-DOS parser
MSDOS partition table detected
containing partition table scheme = 0
got it
Warning: /dev/sda contains GPT signatures, indicating that it has a GPT table. However, it does not have a valid fake msdos partition table, as it should. Perhaps it was corrupted -- possibly by a program that doesn't understand GPT partition tables. Or perhaps you deleted the GPT table, and are now using an msdos partition table. Is this a GPT partition table?
got disk
new partition
added partition start=57777586176 size=62256520704
committed to disk
Error doing BLKPG ioctl with BLKPG_ADD_PARTITION for partition 1 of size 57777586176 at offset 62256520704 on /dev/sda: Device or resource busy
====================================================

[Martijn Heemels (yggdrasil)]

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.

[Evertjan Garretsen (egarretsen)]

After looking throug many forum entries i managed ubuntu to see the installed windows 7 by removing the windows recovery partition. (WARNING: don't do this if you are not familiar with reinstalling windows without using the recovery tools for your computer)

I booted windows and removed the partition in windows. After restarting the Ubuntu installer windows 7 was detected. I read somewhere this is caused by a file that wants to be at the end of the disk and that a minimum of X blocks on the end of the disked should be reserved for this. Using gdisk before i removed the windows recovery partition said: “overlapping the last partition by xx blocks"..

I wanted to dual-boot Ubuntu with Windows, but as i use Ubuntu 99% of the time i just wanted Ubuntu to work, no matter what the costs. So i deleted the recovery partition (after making backups of it using asus tools). And Ubuntu installed just wonderful. Unfortunately the UEFI / GRUB / MBR / whatever problems still don't allow me to start windows, but hey Ubuntu is working just fine!

[Evertjan Garretsen (egarretsen)]

I forgot to mention that i used the Ubuntu Uefi install.

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Launchpad Janitor (janitor)]

[Expired for ubiquity (Ubuntu) because there has been no activity for 60 days.]