Windows Server Backup should recycle storage space on the drive as needed, however it can get to the point where there is not enough space for it do this.

When this happens you need to clear space by deleting old shadow copies on the drive, use the following instructions to do this:

• If the drive doesn't have a drive letter assign it one temporarily

• Open a command prompt

• Run the command vssadmin list shadows /for=F: (where f is the drive letter you have assigned)

• This will tell you how far the shadow copied go back. This will allow you to determine how many can be deleted, if possible keep the current weeks.

• You can then delete them by running the following commands:
  • diskshadow
  • delete shadows oldest F: (this will delete the oldest shadow copy, run this as many times as you need)

• Once you have cleared the desired amount of shadow copies, check there is now a sufficient amount of disk space a few GB should be enough for it to continue recycling space automatically. Then close the command prompt and remove the drive letter from the backup drive (unless it was already there).

The next time the backup runs it should be successful.