VSS timeout exceeded (Code 2426)

Situation

A backup plan failed with the following error message: Error code 2426. VSS timeout exceeded. Volume Shadow Copy service (GetVssFactory:[1]) exceeded the 02:00:00 threshold.

Cause

Cause

A VSS timeout exceeded error usually means the Volume Shadow Copy Service (VSS) could not complete a snapshot within the expected time (2 hours). The most common causes are:

• Stuck or unresponsive VSS writers
  One or more VSS writers may be in a failed or hanging state.
• Another VSS operation is in progress
  Backup, snapshot, or system operation already using VSS can block a new request.
• System performance issues
  High CPU, disk I/O, or low memory can delay snapshot creation.
• Storage problems
  Slow disks, insufficient free space, or shadow copy storage issues.
• VSS services not working properly
  Required services (e.g., Volume Shadow Copy, Microsoft Software Shadow Copy Provider) may be stopped or malfunctioning.
• Third-party software conflicts
  Antivirus, backup tools, or disk utilities can interfere with VSS.
• Windows update issues (applicable to Windows 11 Pro)
  • The April Windows 11 security update KB5083769 may cause issues on systems running Windows 11 Pro (no other editions have been confirmed so far).

Solution

Run the fixVSS tool to automatically resolve VSS-related problems. This helps to resolve most of the mentioned issues. The workarounds for the Windows KB5083769 update issue are described below.

Windows KB5083769 Update Issue

The security update KB5083769 may break VSS (Volume Shadow Copy Service) functionality and other system features. For example:

• The system command vssadmin list writers may hang.
• System counters such as Available Bytes, Committed Bytes, etc., may fail to return values when queried via the registry.

As a result:

• It may be impossible to create a VSS snapshot during backup plan execution and use it for correct system backup.
• Log collection may hang because system counters are read during log preparation.

An official fix or issue description has not yet been published by Microsoft. However, update KB5083631 is currently available. After installing it and rebooting the system, some customers have reported that backup functionality was restored.

How to Check if You Are Affected

1. Open Command Prompt (cmd.exe) as Administrator.
2. Run the command:

vssadmin list writers

3. Check the result:
   • If you see a list of writers that your system is not affected.
   • If you see "Waiting for responses", this means that the issue is present and likely caused by KB5083769.

Workarounds for KB5083769 Update Issue

Option 1

Uninstall the security update KB5083769 and reboot the computer.

Option 2

Wait for an official fix from Microsoft. Our team is still investigating the issue.