I experienced this issue the past week. Veeam threw an error during a backup about it not being able to delete a snapshot. Come to find out, there was a slew of snapshots just sitting there even though the snapshot manager thought there were no snapshots.
Symptoms: You have a VM with a snapshot that says Consolidate Helper- 0
When you try to delete the snapshot you receive an error like so: The VI client logs the following error "Name: Remove snapshot, Target: VMNAME, Task: Unable to access file <unspecified filename> since it is locked".
How it came to be.
Option 1: As you can see from the Veeam Forum Thread "Helper snapshot not removed when vStorage API job is stopped", this error occurs when a Veeam job is aborted. Veeam takes the stance that their software is not responsible for this.
Option 2: a Guest Remediation attempt was aborted.
The Problem: You have a bunch of VMDK files from snapshots that keep on piling up, but all of these snapshots are not seen in the SnapShot Manager.
How to remove all these snapshots.
After trying the steps indicated in VMware's KB Article 1002310 "Committing snapshots when there are no snapshot entries in the snapshot manager", it still did not work.
- Shutdown the VM.
- Clone the VM while it is in it's cold state. This way you won't end up with locked file errors.
- The cloned VM will have removed all previous snapshots and you are back to two discs.
- Delete your original VM when you're ready to take the leap.
New Workaround (help provided by nhawkp)
If you are using Veeam Backup and Replication in Virtual Appliance mode, it may be the culprit. Virtual Appliance mode works by mounting the VMDKs from the VM you are backing up, to the Veeam VM. If an operation is stopped or aborted, the VM's VMDK files may never get unmounted from the Veeam VM. Therefore, trying to delete snapshots will not work because the VMDK is locked.
- Within the VI client, Go to Edit Settings of the VM
- Click on the Hard Disks and look at the location of the VMDK file. Does the VMDK file belong to a different VM that's having problems? No? do the clone trick. Yes? Continue on...
- Remove the virtual disk
- Only remove it from the virtual machine, do not delete files from disk
- The VMDK is now unmounted so snapshot removal can be performed.