How to Resolve Event ID 21 Source VolSnap

Event Type: Error
Event Source: VolSnap
Event ID: 21
The flush and hold operation for volume volume_name was aborted because of low available system memory.

This problem occurs because VSS incorrectly detects low-memory conditions. Low-memory conditions are based on the LowMemoryCondition event. If the LowMemoryCondition event is signed, VSS denies the volume snapshot action.

Install the updated Volume Shadow Copy Service (VSS) rollup package for Windows Server 2003 from Microsoft.

Be sure to select the propoer roll up for the version of Microsoft Windows being used.

VSS hot fix download and details: