If you encounter an error during backup selection, you may have misconfigured or disabled Volume Shadow Copy Services (VSS) drivers. Use the following steps to help resolve the error.
Step 1. Review bbtrace.txt File
Log in to the data source that is encountering the error, and go to the Backup Agent log files. By default, the log files are located in C:\Program Files\Barracuda\Barracuda Backup Agent\log
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Locate the file bbtrace.txt; this is the most recent log file.
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Open bbtrace.txt in Notepad. This file contains data that is helpful in determining the specific error. Each log entry is time stamped, so you will first want to identify when the failed backup occurred based on the Report details page; note that there may be multiple days of log details so it is recommended that you use the search function to find the error.
Search the log file for terms such as Failed or Critical. Once you locate the term, review the associated content to determine the specific error message:
07/23/15 23:07:07 0x0000b7c YVssManager: Bad writer status [Microsoft Hyper-V VSS Writer]: VSS_WS_FAILED_AT_PREPARE_SNAPSHOT- In this example, a VSS snapshot failed during backup selection.
- Note the timestamp in the error, in this example:
07/23/15 23:07:07 - Review your application and System event logs based on the error timestamp, for example 07/23/15 23:07:07, for any additional information about these errors to help resolve the problem.
Step 2. Check VSS Writers
Open PowerShell.
At the PowerShell command prompt, enter the following command:
vssadmin list writersDetermine if the Hyper-V VSS writer is in Stable condition. For example:
C:\>vssadmin list writers
Writer name: 'Microsoft Hyper-V VSS Writer'
Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
Writer Instance Id: {42422b7b-17aa-4cba-9241-0e34f8982f2f}
State: [8] Failed last error: Retryable error
Step 3. Restart or Reboot
You can either restart the Hyper-V process or reboot the server and run a test backup or wait until the next scheduled backup runs.
If the problem persists, contact Barracuda Networks Technical Support.