Removing Duplicate PowerShell modules

Sometimes installing or updating PowerShell modules will result in duplications where more than one version of the same module is installed.

This is typically not a problem but for things like Desired State Configuration (DSC) this can be an issue as DSC requires that you either specify a specific version or only have one version installed.

Solution

To remedy this problem here’s a set of scripts:

Get Duplicate Modules

Get-InstalledModule | ForEach-Object {
    $latestVersion = $PSItem.Version

    Write-Host "$($PSItem.Name) - $($PSItem.Version)" -ForegroundColor Green

    Get-InstalledModule $PSItem.Name -AllVersions |
    Where-Object Version -NE $latestVersion |
    ForEach-Object {
        Write-Host "- $($PSItem.Name) - $($PSItem.Version)" -ForegroundColor Magenta
    }
}

Get-DuplicateModule.ps1 sample output

Uninstall Duplicate Modules

Get-InstalledModule | ForEach-Object {
    $latestVersion = $PSItem.Version

    Write-Host "$($PSItem.Name) - $($PSItem.Version)" -ForegroundColor Green

    Get-InstalledModule $PSItem.Name -AllVersions |
    Where-Object Version -NE $latestVersion |
    ForEach-Object {
        Write-Host "- Uninstalling version $($PSItem.Version)..." -ForegroundColor Magenta -NoNewline
        $PSItem | Uninstall-Module -Force
        Write-Host "done"
    }
}

Uninstall-DuplicateModule.ps1 sample output

Notes

• The -AllVersions switch of Get-InstalledModule is only available when specifying a specific module, thus these scripts suffer from the N+1 Query Problem.

• Inspired by http://sharepointjack.com/2017/powershell-script-to-remove-duplicate-old-modules/.