During NetVault Backup Plug-in Hyper-V backups we can see Hyper-V related errors in the Windows event logs:
Log Name: System
Source: VDS Basic Provider
Date: 6/14/2016 01:01:16
Event ID: 1
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: bkb.test.com
Description:
Unexpected failure. Error code: 48F@01000003
This event seems to be related to snapshots of VMs performed before the backup as the NVBU logs show at the same exact time:
2016/06/14 01:01:17 11867 Data Plugin BKB VM [testA]: Created VSS snapshot