Symptoms

When you open System Restore settings, one or more drive letters may be missing in the list of Available drives. As a result, monitoring may not be enabled for the missing drives.

Solution

There are two ways to fix the problem. In our testing, the first method did fix the problem without removing the existing System Restore points. However, your mileage may vary and there is no guarantee for the existing restore points.

Method 1 - Renaming the drivetable.txt file

Drivetable.txt is the file which holds the System Restore drive letters list, and stores other configuration information such as System Restore space allocation information for each drive. This file is present in one of the sub-folders of the System Volume Information folder, present in the %Systemdrive%

> Click Start, Run and type %Systemdrive%

> Select the System Volume Information folder

> Note that "System Volume Information" (SVI) folder is super-hidden by default, and you need to configure the Folder Options dialog to show all hidden and protected files.

> Then look in for a file named drivetable.txt in one of the sub-folders.

> Rename the file drivetable.txt to old_drivetable.txt.

> Undo the above Permissions (again, for NTFS only), and restart Windows.

A new drivetable.txt file will be generated and all the drives will now be monitored by System Restore.

Method 2 - Reinstalling System Restore