VDR backups failing due to error -390 ( cannot quiesce virtual machine)

This has been a frustrating error that started out of nowhere. Suddenly the backups of one of my VM's just stopped working. This VM does not do alot of transactions, not does it generate alot of disk activity. The error messages tend to suggest that. However, I tried powering down the VM to get the snapshot to work so the backup would complete, that worked as an interrum solution. Long term I moved the VM to other LUNS, I tried going from think to thick provisioned, that didn't help either. Finally got it fixed, I uninstalled the VMW tools, then reinstalled the tools with a 'custom' install and unchecked the option for VSS (from a suggestion I read). This seems to have fixed the issue and the online backup is running right now for the first time in a long time.