Deleting Previous MDT Build Logs with this PowerShell One-Liner

If you have the SLShare variable defined in MDT to write logs to the specified UNC path and the SLShareDynamicLogging defined to write to the same path including the %ComputerName%, you have probably run into the issue of the logs being enormous. This is since each time a system is reimaged with the same computer name, the new logs are appended to the old logs, and they do get big.

This PowerShell one-liner will delete the folder containing all of the old logs if it exists. To get this to work, you will need to get the full UNC path to the ZTIUtility folder, which I found is located at %DeployRoot%\Tools\Modules\ZTIUtility. To map to this, you need to explicitly define the UNC path as the PowerShell one-liner cannot read the task sequence variable %DeployRoot% until this module is loaded.

To use this in MDT, I created a Run Command Line task as shown below.

The task was placed into the Initialization phase, so the log directory is deleted at near the start of the task sequence.

Here is the  one-liner. You will need to set the executionpolicy as it will be initially set to restricted and you will need to update <UNC Path to the MDTDeploymentShare> to the path of the MDT deployment share.

 powershell.exe -executionpolicy bypass -command "&{import-module '<UNC Path to the MDTDeploymentShare>\Tools\Modules\ZTIUtility';$LogDir=$TSEnv:DEPLOYROOT+'\Logs\'+$TSEnv:OSDCOMPUTERNAME;If ((Test-Path $LogDir) -eq $true) {Remove-Item -Path $LogDir -ErrorAction SilentlyContinue -Recurse -Force}}"