VDR Integrity Check failure (index invalid/damaged)

Our daily VDR backups have stopped running because if the inegrity check failing due to the index being invalid/damaged.

We have ran manual integrity checks and the same problem occurs.

Vsphere client does not report any damaged backups.

We have removed store.lck file from the backup destination.and confirmed nothing else is accessing the backup destination.

We have restarted the VDR appliance and ran another integrity check and the porblem still occurs.

Does anyone have any ideas for what we can try next ?

We are using VDR version 2.0.0.1861

Thanks in advance