Problems with VSS

The problem occurs when VSS (Volume Shadow Copy Service) cannot be started due to an unexpected error.

Solution

The following have been described 5 ways to solve the problem with VSS.

First way - you have multiple backup solution installed.

Many applications to perform backups have their own snapshot manager, which can cause conflicts with another backup solution installed on the computer.

If you have several applications to perform backup installed on your computer, uninstall them, except of  Xopero.

It is a good practice to have one software to do backups at one time.

After uninstalling programs you should start cleaning the registry -e.g. by CCleaner.

Second way - Shadow storage is not configured or capacity is too low.

VSS requires space on each volume to create and store snapshots. Ways to configure depend on the operating system, it is advisable to check the Microsoft Knowledge Base which steps you must take in case of your system.

Steps and commands to change the volume of the shadow storage are the same for each.

To check and change the size use the following commands:

1. Check the current size: vssadmin list shadowstorage
2. Change size: vssadmin Resize ShadowStorage /For=X: /On=X: /Maxsize=YY%

In place of YY specify the size in percentage and in place of X: type the drive letter for which you want to resize shadow storage.

It is recommended to set the amount at 30% to avoid errors related to Shadow Copy.

Third way - Create a backup of mapped drives.

The Windows VSS service can only create snapshots of drives connected locally to the machine that you are taking the snapshot of.

This error can occur when you try to create a snapshot of network drive which is seen as a local by operating system (eg. Mapped network drive).

To solve the problem, disconnect the drive and re-run the backup.

Fourth way - Previous VSS snapshot is still running.

Snapshot manager of Windows is able to perform only one snapshot at a time. If the process of creating a snapshot is running during backup, so backup fails. Stopping and restarting the VSSa can solve this problem.

In order to do this run command line as administrator and type the following command:

• net stop vss
• net start vss

Correct server restart does not solve the problem because of the manager snapshot cleanup.

Fifth way - Using an extended partition as a backup destination.

Performing VSS snapshot may fail because there are extended partition.

In order to ascertain whether the extended partition is used:

1. Use these commands on the command line: fsutil fsinfo ntfsinfo,
2. Look for the bytes per sector output,
3. if the size of the sector is greater than 512 (usually this will be 4096), the partition is extended.

The problem occurs at the hardware level and disk format does not fix it. To solve the problem, try to start the USB device, with value of bytes per sector is 512.

The problem occurs mostly on Windows earlier than Windows Server 2012/Windows 8.

Six way - Rebuilding VSS's DLL using the Regsvr32 tool

Execute the following commands from the command line or in the command script, and then restart the computer.

cd /d %windir%\system32
net stop vss
net stop swprv
regsvr32 /s ole32.dll
regsvr32 /s oleaut32.dll
regsvr32 /s vss_ps.dll
vssvc /register
regsvr32 /s /i swprv.dll
regsvr32 /s /i eventcls.dll
regsvr32 /s es.dll
regsvr32 /s stdprov.dll
regsvr32 /s vssui.dll
regsvr32 /s msxml.dll
regsvr32 /s msxml3.dll
regsvr32 /s msxml4.dll
vssvc /register
net start swprv
net start vss