“Failed to truncate transaction logs for SQL instances: MICROSOFT WID”

Challenge

Job with truncation enabled shows warning: 

Failed to truncate transaction logs for SQL instances: MICROSOFT##WID

Note: This KB article only applies if the specified instance is named MICROSFT##WID.

Cause

After applying update 3 for Veeam Backup & Replication v8, we attempt to connect to an internal Microsoft Database during log truncation.

The Task.<vmname>.<refid>.log file for the VM in the job will contain:  
 

Error VssControl: TruncateSqlLogs failed (System.Exception)
Error at Veeam.Backup.VssProvider.CVssControl.TruncateSqlLogs(Guid jobId, CCredentials creds)
Error at Veeam.Backup.Core.CViGuestVssFreezer.TruncateSqlLogs(Boolean bSafe)
Error Failed to process 'TruncateSQLLog' command.
Error Failed to truncate transaction logs for SQL instances: MICROSOFT##WID. Possible reasons: lack of permissions, or transaction log corruption. (System.Runtime.InteropServices.COMException)
Error at VeeamGuestHelperCtrlLib.IVeeamVssProvider.TruncateSqlLogs(Guid jobUid, String sqlLogin, String sqlPwd)
Error at Veeam.Backup.VssProvider.CVssControl.TruncateSqlLogs(Guid jobId, CCredentials creds)

Solution

This issue is fixed in Veeam Backup & Replication v9.

If you are unable to upgrade to v9, please contact Veeam Support and reference Bug# 59525.

More Information

This issue only applies to 8.0.0.2084, and for the MICROSOFT##WID instance.
For any other truncation issues, please see the following KB: https://www.veeam.com/kb2027