A Veeam Agent for Microsoft Windows Backup Job or Veeam Backup & Replication Backup Job with Application-Aware Processing enabled fails while attempting to process a server with ACT! Software installed, the job displays the following error:

Failed to create snapshot. Error code -2147212300. 'Backup job failed.
Cannot create a shadow copy of the volumes containing writer's data.
A VSS critical writer has failed. Writer name: [SqlServerWriter]. Class ID: [{a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}]. Instance ID: [{1d68f503-11fd-4591-9cf4-90e034386ae9}]. Writer's state: [VSS_WS_FAILED_AT_PREPARE_SNAPSHOT]. Error code: [0x800423f4].'
Cannot create a shadow copy of the volumes containing writer's data.
A VSS critical writer has failed. Writer name: [SqlServerWriter]. Class ID: [{a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}]. Instance ID: [{1d68f503-11fd-4591-9cf4-90e034386ae9}]. Writer's state: [VSS_WS_FAILED_AT_PREPARE_SNAPSHOT]. Error code: [0x800423f4]. (System.Exception)

Correlated with the Backup Job failure, the following error is found within the Guest OS's Windows Application Event Log:

Log Name:      Application
Source:        SQLWRITER
Event ID:      24582
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      TEST
Description:
Sqllib error: Failed to create VDS object. hr = 0x80770005.
Log Name:      Application
Source:        SQLVDI
Event ID:      1
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      TEST
Description:
SQLVDI: Loc=IdentifySQLServer. Desc=Initialize. ErrorCode=(1332)No mapping between account names and security IDs was done.
. Process=5728. Thread=70504. Client. Instance=ACT7. VD=.

Perform the following steps to fix the issue:

1. Open SQL Server Configuration Manager.
2. Click the SQL Server Services node.
3. Open the Properties of the instance mentioned in the Application Event error. (e.g., SQL Server(ACT7))
4. Change the Log On from [ Built-in account: Local System ] to [ Built-in account: Local Service ]