VSS Writers: How to fix Windows Server VSS issues

What Are VSS Writers?

VSS writers (Volume Shadow Copy Service writers) are software components that allow the Volume Shadow Copy Service in Windows to take a consistent snapshot of data on a disk volume. When the VSS service is triggered, it communicates with VSS writers to prepare the data on the disk volume for snapshot creation.

VSS writers are typically included with applications that store data on disk volumes, such as databases, email servers, and file servers. These writers are designed to provide a way for the VSS service to ensure that the data on the disk is in a consistent state when a snapshot is taken.

Each VSS writer is responsible for preparing a specific application or component for snapshot creation. For example, the Microsoft SQL Server VSS Writer prepares a SQL Server database for snapshot creation by flushing all pending transactions to disk and pausing new transactions until the snapshot is complete.

VSS writers play a critical role in ensuring the integrity of backup and restore operations, as they help ensure that the data being backed up or restored is consistent. Issues with VSS writers can cause problems with backup and restore operations, leading to data loss or corruption.

If you are experiencing issues with VSS writers, you may need to troubleshoot the specific writer that is causing the problem or seek assistance from a professional IT support technician.

My Experience With VSS Writers

I really hate VSS writers; mostly, in older OS, the writers become damaged or corrupt, or out of date, versions overwritten by Windows updates. You name it! However, any application that needs a snapshot of the operating system, usually C:\, requires VSS to perform the action.

I most frequently bump into these issues with TSM and P2V conversations.

How to Troubleshoot VSS Writer Issues

To re-register the DLLs (from the Admin command prompt)

First, you must work out if you run Windows in 32-bit or 64-bit mode. (winver.exe will tell you if you running x64)

The first thing to check it the state of your VSS drivers. Open a command prompt as Administrator and type:

vssadmin list writers

This will display your installed writers and their current status:

For 32bit system

First, you need to stop the VSS writer, and you may get a message here about, “the service is not started”; just proceed onwards.

Open Command Prompt as Administrator and type

net stop vss

net stop swprv

This will ensure you have no active VSS in use.

Next, from the Command prompt, type

cd /d %windir%\system32

Then enter the following and press Enter each time

regsvr32 ole32.dll[Press Enter]
regsvr32 vss_ps.dll[Press Enter]
regsvr32 /i swprv.dll[Press Enter]
regsvr32 /i eventcls.dll[Press Enter]
regsvr32 es.dll[Press Enter]
regsvr32 stdprov.dll [Press Enter]
regsvr32 vssui.dll[Press Enter]
regsvr32 msxml.dll[Press Enter]
regsvr32 msxml3.dll[Press Enter]
regsvr32 msxml4.dll[Press Enter]
Vssvc /Register [Press Enter]

For 64bit system

Open Command Prompt as Administrator and type

Net stop vss
Net stop swprv

This will ensure you have no active Writers in use.

Next, from the Command prompt, type

cd /d %windir%\system32

Then enter the following and press Enter each time

regsvr32.exe /i %windir%\system32\eventcls.dll  [Press Enter]
regsvr32.exe /i %windir%\system32\swprv.dll [Press Enter]
regsvr32.exe %windir%\system32\vssui.dll[Press Enter]
regsvr32.exe %windir%\SysWOW64\vss_ps.dll[Press Enter]
regsvr32.exe %windir%\SysWOW64\msxml.dll[Press Enter]
regsvr32.exe %windir%\SysWOW64\msxml2.dll[Press Enter]
regsvr32.exe %windir%\SysWOW64\msxml3.dll[Press Enter]
regsvr32.exe %windir%\SysWOW64\msxml4.dll [Press Enter]
regsvr32.exe %windir%\SysWOW64\ole32.dll[Press Enter]
regsvr32.exe %windir%\SysWOW64\oleaut32.dll[Press Enter]
regsvr32.exe %windir%\SysWOW64\es.dll[Press Enter]
regsvr32.exe %windir%\SysWOW64\comsvcs.dll[Press Enter]
vssvc /register[Press Enter]

VSS are integral components that facilitate the creation of consistent snapshots of data on disk volumes in Windows. While they are essential for backup and restore operations, issues with VSS can lead to challenges in these processes. Personal experiences, like those shared, emphasize the importance of maintaining and troubleshooting VSS, especially in older operating systems. The provided troubleshooting steps for both 32-bit and 64-bit systems offer a comprehensive guide to address common VSS writer problems, ensuring the integrity and consistency of data snapshots. Whether you’re an IT professional or an end-user, understanding and effectively managing VSS is crucial for safeguarding your data.