Converting from GPT to MBR

Yes - mostly. However, it's still recommended to create an Entire Disk Image backup of the drive (or at least any important files) before making partitioning changes.

Also, depending on the layout of the existing partitions, you may need to make some additional changes after the conversion.

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From the DD 11 manual:

The program lets you convert a disk from GPT to MBR with the following implications:

• All volumes of the disk will be logical
• Boot volumes (if any) will be unbootable until you convert them to primary volumes—see Converting a logical volume to primary (p. 35)
• Volumes that allocate more than 2 TB from the beginning of the disk become inaccessible

Well, part of my problem is that I can't seem to access the drive. It shows up in Disk management under Win 7 as well as Acronis, but no drive letter appears and I can't get to the files. Through Acronis browse file feature I can see the files, but I still have no way to back it up.

Will Disk Management allow you to assign drive letters? Right-click on the partition and select Change Drive Letter and Paths....

You should also be able to change the drive letter using DD 11.

Thanks for responding Mud,

Ya for some reason it doesn't work. Once I commit, it just goes back to being blank!

Is there 'partmgr' in upperfilters?

Not sure what the upperfilters are. Using Acronis 11, please see attached screen.

UpperFilters is a value in the Registry (found here: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318}).

When you tried to change/set the drive letter did you use Disk Management or DD? I would try Disk Management if you didn't.

If that doesn't work, you could try booting to the DD CD and changing the drive letter from there. Maybe it will stick if Windows isn't running.

PartMgr is there as well as "snapman"

I created the boot disk, booted in and Acronis can see the drive letter in there!

Yikes! Anyways, that was actually my root problem (that I was hoping to convert to MBR would resolve). I installed a new drive, windows asked me to format GPT and I said ok. After getting a drive letter, I copied all my archive stuff onto the new drive. Then on reboot, I couldn't see it anymore!

Anymore ideas?

Does the option to change the drive letter show up in Disk Management? I assume you've tried this, but you didn't answer the question.

Did you try changing the drive letter when booted to the DD CD?

Is the problem only on this particular drive? Do you have another drive (a spare or old drive, for example) that you could connect and configure as GPT and see if it also has the problem?

If you boot to the Windows 7 DVD and enter Repair Mode, does the partition get assigned a letter and can you see the contents normally (dir h:, for example)?

I just realized that the GPT was formatted as primary...could that be a reason?

Can DD change primary to logical?

GPT partitions can't be Logical.

I think I would copy off the data on the drive, wipe it (the start, at least), and then reinitialize it and see if the drive letter will stick.

Did you ever boot to the Windows DVD and see if the drive letter shows up?

Hmm, I wonder if that is the issue. I can't access the drive to actually back anything up unfortunately!

I booted through Windows DVD, went to repair, entered DOS prompt, could not find the drive.

Does the drive letter assignment show up in the Registry in the MountedDevices key? This would be located at HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices. I'm curious if it's corrupted somehow. Maybe you could post a screenshot of it.

TI should be able to back up the partition even without a drive letter (as should other imaging programs). I wonder if you would be able to Mount the backup with TI and access the data.

Hey Mudcrab,

Sorry for such a long delay. I didn't have TI, but I finally bought it, backed up, converted to MBR, data seems like it's there, but I still can't access it. Attached a screen of the registry...does look weird, but I can't interpret!

What drive letter is assigned to the partition?

Have you tried using a high letter like X: or Z: ?

Is it possible to Explore/Mount the backup image you created and access the data?

Thanks for your help mudcrab!

I was able to use TI and explore the backup I made. I tested the restore onto a working partition and that worked. So I nuked the GPT drive completely, reformatted, and restored onto the new partition (now MBR). Everything worked. I appreciate your help, thanks so much!