This article provides instructions for resolving the There is insufficient storage space on the VSS snapshot volume(s) to take a snapshot error.
Replay snapshots fail with the There is insufficient storage space on the VSS snapshot volume(s) to take a snapshot error.
Unable to take VSS snapshot and transfer data for <volume letter(s)>: There is insufficient storage space on the VSS snapshot volume(s) to take a snapshot. This error occurs because the size of the snapshot created by Replay is larger than the available space in the storage disk.
Free up disk space, or backup your Windows registry and then modify the HKLM\System\CurrentControlSet\Services\VolSnap\MinDiffAreaFileSize registry setting to a smaller number.
Refer to Microsoft KB article 925799 at http://support.microsoft.com/kb/925799 .
Note: Microsoft warns: “Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.”
This MS Support Knowledge Base article also refers to more fundamental “information about how to back up, restore, and modify the registry” at Microsoft KB article 256986 http://support.microsoft.com/kb/256986 .