For those who don't already know, originally posted from the System Restore Team blog, many users may have experienced the loss of restore points caused by dual-booting with Windows XP.

The problem: 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.

For more information, please see:
http://blogs.technet.com:80/filecab/...14/441829.aspx