Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm in the process of installing Windows 7/64 on a system with Windows XP/32 on it. During my research, I read about a problem that occurs in the dual boot scenario where Windows XP deletes Windows 7's restore points when it accesses the Windows 7 volume:

I found a workaround but it seems pretty painful since it appears to involve using the registry to make the Windows 7 volume appear invisible or "offline" to Windows XP, making sharing disk data between the two O/S annoying since you have to use something like an external storage device to get it done:

I was wondering if this problem only occurs with systems that have both O/S installed on the same physical hard drive (in different partitions)? In my case, I will have each O/S on a completely separate physical hard drive.

Any other tips would be appreciated.

-- roschler

share|improve this question
up vote 2 down vote accepted

Windows XP automounts every disk it detects, including external or removable hard disks. As part of the automounting process, NTFS writes to the disk, and these writes are detected by the volsnap.sys driver in Windows XP. Because this version of volsnap.sys does not recognize the persistent shadow copies (also known as restore points) made by the volsnap.sys driver in Windows Vista, Windows XP cannot maintain the integrity of the shadow copy storage area and deletes the shadow copies to avoid corrupting them. Note that dual-booting Windows Vista with Windows Server 2003 or Windows XP Professional x64 Edition will also result in the shadow copies being deleted.

Source of Information

I worked around this issue on a Dell I had, Before booting XP, I could go into the bios and disable any hard drive I needed, then when XP loaded, it did not see my W7 on the secondary drive, not all bios's have this nice feature anymore.

share|improve this answer
Thanks Moab. Too bad. I guess once I've gotten everything moved over from XP to 7 I'll institute the registry fix to hide the Win 7 partition from XP. – Robert Oschler Jul 1 '11 at 6:02
You can disable mounting of that disk in an earlier operating system to workaround this problem instead of using the BIOS: – Sam Brightman Sep 18 '15 at 5:43

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.