This error may be caused by a hardware, file system or Operating System fault causing corruption to the Disk Safe file. Disk Safe viability, in part, relies on the stability of the underlying hardware and Operating System of the host storage device.
The safest solution is to create a new Disk Safe as soon as Server Backup reports that the database disk image is malformed. In some situations, the Disk Safe may still be usable for restoring recovery points that were created before the Disk Safe reported a corruption. However, we have no way to determine the extent of the corruption or if the workaround mentioned below will be able to repair the Disk Safe. In addition, we do not expect that a corrupt Disk Safe will be successful in a bare metal restore.
You may attempt to repair the Disk Safe by running a Disk Safe Verification (DSV) task (introduced in Server Backup v5.2.0) against the Disk Safe with the malformed image. The DSV will check the most recent recovery point to ensure all blocks are accounted for. If the disk safe fails to verify, a repair attempt will be made during the next replication task which will attempt to reconcile any missing blocks from the recovery point.