A VADP backup cannot create a VM snapshot and fails with the error: "StartBackupSession failed. error: Create snapshot task failed: The operation has been disabled by the guest operating system (VixDiskLib_PrepareForAccess returned error code: 20005) An error occurred while saving the snapshot: Exceeded the maximum number of permitted snapshots. Failed OpenListing for..."
The special parameter "snapshot.maxSnapshots " for a Virtual Machine is configured to NOT allow a snapshot creation.
To re-configure the special parameter "snapshot.maxSnapshots " for a Virtual Machine to allow snapshots creation, please use following steps:
- Shut down the Virtual Machine.
- Right-click on the Virtual Machine in the vSphere Client and click Edit Settings.
- Click the VM Options tab, click on Advanced, then select the Configuration Parameters option.
- Search for a string name called snapshot.maxSnapshots and increase it's value.
- Click OK to save the changes.
- Power on the virtual machine and run the VADP backup.
Please also refer to the VMware KB#1031280.