You are protecting Windows Server 2008 R2 with Acronis software.

Backup fails with the following error messages:

Error code: 1098825
Fields: {"$ module": "disk_bundle_vsa64_xxxxx"}
Message: Locking of volume snapshot failed.
Error code: 9
Fields: {"$ module": "disk_bundle_vsa64_xxxxx", "code": 3758096391}
Message: Already blocked.

While checking VSS doctor report or Windows Application Event log you find the following (or quite similar):

Volume Shadow Copy Service error: Unexpected error calling routine RegOpenKeyExW (-2147483646, SYSTEM \ CurrentControlSet \ Services \ VSS \ Diag, ...). hr = 0x80070005, access denied.

You are protecting Windows Small Business Server 2011 Standard.

When checking VSS doctor report or Windows Application Event log you found the following (or similar) warning for "spsearch account" and 1376 status code:

Type: Warning
Source: VSS
Message: Volume Shadow Copy Service error: Unable to resolve spsearch account with status 1376. Check connection to domain controller and VssAccessControl registry key. Operation: Collecting Write Process Data Asynchronous Operation Execution Context: Execution Context: Requestor Current Status: GatherWriterMetadata Error Details: Error: NetLocalGroupGetMemebers (spsearch), 0x80070560, The specified local group does not exist.
InstanceId: 8230
SearchLink: https://www.google.com/#newwindow=1&q=VSS+event+id+8230


Acronis True Image supports VSS-aware databases for both disk-level and file-level backup.


Acronis software may give errors, freeze or produce other undesired effects when there are issues with parts of the computer environment it operates in:


Disk partitions, file systems

Backup fails with:

The backup has failed because 'VSS Writer' has timed out during snapshot creation



Windows error: (0x800423F2) VSS writer 'System Writer' with class ID 'E8132975-6F93-4464-A53E-1050253AE220' has timed out. This may be caused by too intensive I/O on the machine at the backup start time. Try to re-schedule the backup to some different time. To troubleshoot VSS issues, download and run Acronis VSS Doctor available at https://www.acronis.com/en-us/personal/vss-diagnostic-free-tool/


Activity fails with one of the following errors:

Windows error: (0x800705B4) This operation returned because the timeout period expired


Operating system error: This operation returned because the timeout period expired


Backup activity fails with the following error:

Operating system error: The shadow copy provider had an error. Check the System and Application event logs for more information.

  1. You use Acronis Backup 12.5 or Acronis Cyber Cloud
  2. You run a backup of a Microsoft SQL database
  3. Backup fails with the following error:

Problems detected that may cause a VSS snapshot failure. Trailing spaces in the path. To remove the trailing spaces, run the T-SQL command: ALTER DATABASE MODIFY FILE


Backup fails with: 

Windows error: (0x80070015) The device is not ready


Backup fails with: 

Windows error: (0x800705AA) Insufficient system resources exist to complete the requested service

While using the VSS backup option to back up complex applications, you may encounter issues with creating volume snapshot/shadow copy. This article provides instructions on how to troubleshoot and resolve such issues.


Application-aware backup fails with one of these errors:

Error 1

Error code: 34865165
Fields: {"$module":"aavb_backup_command_addon_vsa64_23140"}
Message: Failed to get the metadata from the 'VMware Snapshot Provider' extension library.
Error code: 65520
Fields: {"$module":"aavb_backup_command_addon_vsa64_23140","code":2147942402}
Message: The system cannot find the file specified


Disk/partition backup fails with: 

Windows error: (0x80070001) Incorrect function

This article applies to backups of Hyper-V VMs performed by Agent for Hyper-V (agent-less)



Prior to performing the backup, make sure that the below prerequisites are met:

1. Hyper-V Integration Services must be up-to-date and running inside the virtual machine(s).

2. In order to avoid VM going into "saved" state during backup, make sure that the Integration services -> Backup (Volume checkpoint) option is enabled in VM settings in Hyper-V Manager.


Backup fails with: 

Windows error: (0x8007001F) A device attached to the system is not functioning


Backup fails with: 

Unknown status

VSS-Backup fails with "The shadow copy provider had an unexpected error while trying to process the specified operation". To solve this issue, troubleshoot the VSS provider mentioned in the message.

Backup task hangs at "Calculating time remaining..."