Knowledge Base

The VMware Knowledge Base provides support solutions, error messages and troubleshooting guides
Search the VMware Knowledge Base (KB)   View by Article ID

Snapshot consolidation is failing in NBD mode whenever we have NFC timeout. (2050453)


  • When backing up a virtual machine in NBD mode, the backup completes, but deleting the snapshot fails with a consolidation error.
  • While the snapshot is removed, the virtual machine is left in a state where it requires consolidation. Subsequent consolidation attempts also fail due to locked files.
  • In the hostd.log file, you see the error:

    TaskCreated : haTask-14-vim.vm.Snapshot.remove-158582742

    [67380B90 info 'DiskLib' opID=ecacd868-b5] DISKLIB-LIB: Cannot remove extent `/vmfs/volumes/50f6af3f-5b1

    Failed to consolidate disks in Foundry: Error: (15) The file is already in use


The issue occurs only when the backup application opens all disks of a virtual machine simultaneously, then proceeds to back them up one at a time. If there is a large amount of data to back up, it causes long idle times on the other open disks and these connections can be closed by an external application due to inactivity. This results in the disks not being closed correctly and the redo log files remain locked.


This issue is resolved in VDDK 5.5 release.

To workaround the issue when you do not want to upgrade, back up one disk at a time, ensuring that there is only one virtual machine disk open at one time per job.

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


  • 2 Ratings

Did this article help you?
This article resolved my issue.
This article did not resolve my issue.
This article helped but additional information was required to resolve my issue.
What can we do to improve this information? (4000 or fewer characters)
  • 2 Ratings