BA2900: Shadow Copy Protection Mode encountered an unexpected problem¶
| Error code | Product | Applies to |
|---|---|---|
| BA2900 | BackupAssist | For BackupAssist 8.3.0 or later. |
Description¶
Shadow Copy Protection Mode is a Legacy System Protection option that guards the backup history (restore points) on the destination against Volume Shadow Copy (VSS) faults. BA2900 is the general catch-all it reports when an unexpected VSS problem occurs while it reads or manages shadow protection on the mounted destination - often a Data Container (VHDX) on a NAS. It can appear alongside a BA101 (Windows Imaging Engine) major warning.
There are two common real-world causes:
- A Windows cumulative update that breaks VSS access to a Data Container on a NAS (reported classically on Synology), producing a VSS "provider veto" error - addressed in current BackupAssist builds.
- Genuine file-system or disk faults on the source system drive or on the backup destination disk.
Resolution¶
Resolution 1 - Update BackupAssist (recommended)¶
The NAS Data Container VSS failure that follows certain Windows updates was fixed in a later build. Upgrading to a current version of BackupAssist resolves that case.
Resolution 2 - Check permissions on the Data Container (direct-to-NAS destinations)¶
If you back up to a Data Container or directly to a NAS, make sure the Backup User Identity has Full Control of the container file and its parent folder. The documented workaround for the NAS VSS case is to grant Full Control to Everyone on the container file (and its parent folder) so BackupAssist can mount and protect it.
Granting Full Control to Everyone removes the access restrictions on those files, so try the narrower option first: grant Full Control only to the Backup User Identity (and, if the share requires it, the specific account the NAS uses). Use the Everyone permission only as a temporary step on a trusted, access-controlled share, and tighten it again once the cause is understood.
Resolution 3 - Check disk and file-system health¶
Run "chkdsk /f /r" on both the source system drive and the backup destination, and replace any destination disk that reports errors. BA2900 can be a genuine sign of a failing destination disk or file-system corruption.
Note: "chkdsk /f" needs exclusive access to the volume, so it dismounts the volume while it runs. If the volume is in use - the system drive, for example - it cannot run immediately; Windows schedules the check for the next restart and prompts for a reboot. Plan to run it outside backup and production hours.
Resolution 4 - Recently installed Windows updates (advanced)¶
If the problem began immediately after a Windows cumulative update and you cannot upgrade BackupAssist straight away, removing that update has restored backups in confirmed cases. Upgrading BackupAssist is the preferred fix.
Note on the backup report¶
The backup report shows: Shadow Copy Protection Mode encountered an unexpected problem. It may appear together with a BA101 Windows Imaging Engine warning.
| Last updated | Created | Further assistance |
|---|---|---|
| 15th Sep 2026 | 02nd Mar 2015 | BackupAssist Support page |