PowerShell Script Execution Troubleshooting Advice

General Advice

This section will provide advice on changes you can make to your script to help with troubleshooting.

For this example, here is a simple script that identifies the most recently modified file in a folder and then copies it to a folder.

$LatestLog = get-childitem -Path 'C:\MonitoringLogs\' | sort-object LastWriteTime | select-object -last 1
Copy-Item $LatestLog.FullName D:\Backup\

• Add logging to the PowerShell script itself so that you can check what errors the script may have thrown when being executed. This can be done by adding 'Start-Transcript -path C:\temp\scriptlog.txt' to the first line of the script and adding 'Stop-Transcript' to the last line.
  

  Start-Transcript -path C:\temp\scriptlog.txt
  $LatestLog = get-childitem -Path 'C:\MonitoringLogs\' | sort-object LastWriteTime | select-object -last 1
  Copy-Item $LatestLog.FullName D:\Backup\
  Stop-Transcript
  

• After adding the Start-Transcript cmdlet to the script, make the actions within your script more verbose. For example:
  • If the script contains a variable, have the script announce the variable using Write-Host so that it appears in the transcript log. For example:
    

    Start-Transcript -path C:\temp\scriptlog.txt
    $LatestLog = get-childitem -Path 'C:\MonitoringLogs\' | sort-object LastWriteTime | select-object -last 1
    Write-Host $LatestLog
    Copy-Item $LatestLog.FullName D:\Backup\
    Stop-Transcript
    

  • If the script uses a command that can have a -verbose flag added, add it so that the transcript log will contain more information. For example:

    Start-Transcript -path C:\temp\scriptlog.txt
    $LatestLog = get-childitem -Path 'C:\MonitoringLogs\' | sort-object LastWriteTime | select-object -last 1
    Write-Host $LatestLog
    Copy-Item $LatestLog.FullName D:\Backup\ -verbose
    Stop-Transcript
    

Conclusion

Now, this simple script, when run, will also write out a log file containg:

• Full PowerShell headers documenting what command was used to call it, as well as what user ran it.
• What file it determined to be the $LatestLog
• What the outcome of the Copy-Item command was.

5. Observe the outcome. If it fails, resolve the errors shown, save the script, and test it again.

Service Account is LocalSystem

If the account assigned to the Veeam Backup Service is Local System, which is the most common configuration, testing the scripts manually will be a bit more difficult. There are two options for causing a script to be run using the account Local System.

4. Observe the outcome. If it fails, resolve the errors shown, save the script, and test it again.

Option 2: Test the Script Using Task Scheduler to Run the Script As SYSTEM

1. Open Task Scheduler.
2. Create a New Task.
   • Name the Task.
   • On the General tab, in the Security options section, click 'Change User or Group...' and enter the username SYSTEM.
   • On the Actions tab, add an action to "Start a program." 
     • For the Program/script, enter: powershell.exe
     • For the Arguments field, update the 'C:\path\to\script.ps1' in the following example and insert it.

       -ExecutionPolicy ByPass -Command "& {try {& 'C:\path\to\script.ps1' -ErrorAction Stop } catch { exit 1 }}"
       

3. Run the Task.