Check for exclusive lock held by a Virtual Machine Backup solution proxy VM.
- Select the backup solution proxy VM from vSphere Inventory
- Right click the VM > Select "Edit Settings..." or click on the Actions button in the VM summary > Select "Edit Settings..."
- Expand the Hard disk and validate if there are any VM disks matching the files you wish to remove
- Consult your back up solution if necessary on impact of removing a disk from the Proxy VM before continuing
- Select "Hard disk", Select "Remove device"
- Click on OK
- Retry the file removal operation
For corrupt CTK files follow
KB2013520Incase the above steps doesn't resolve the issue
Engage VMware Support for assistance