"DiskLib_NotifySnapshotPrepare: FiltLib failed to notify snapshot prepare" is logged during snapshot creation

Products

• VMware vSphere ESXi 8.0

Issue/Introduction

When taking a snapshot of a virtual machine, the following log entry is recorded in the vmware.log file:

YYYY-MM-DDTHH:MM:SS.sssZ Er(02) vmx esxui-d399-deb8 DISKLIB-LIB_CREATE   : DiskLib_NotifySnapshotPrepare: FiltLib failed to notify snapshot prepare: Operation completes asynchronously

Environment

VMware vSphere ESXi 7.x
VMware vSphere ESXi 8.x

Cause

This log message indicates that the disk processing operation triggered during the snapshot creation was initiated asynchronously.

This is an internal status notification from the Filter Library (FiltLib) stating that the request is being processed in the background. It does not indicate a functional failure or a timeout of the snapshot operation itself.

Resolution

This message can be safely ignored.

It is expected behavior for this log to appear even when the snapshot task completes successfully. As long as the snapshot is created without any other associated error messages, no further action is required.

Additional Information

スナップショット作成時に "DiskLib_NotifySnapshotPrepare: FiltLib failed to notify snapshot prepare" が出力される (Japanese)