PowerShell Script: Quickly Convert SIDs to Usernames

Posted on April 20, 2026 Updated on April 16, 2026

Have you ever looked at a security log or a orphaned folder permission and seen a string like S-1-5-21-3623811015-3361044348-30300820-1013? Those are SIDs (Security Identifiers). While they are great for the Windows OS, they are nearly impossible for humans to read.

If you have a list of these SIDs from an audit or a log file, you don’t have to look them up one by one. This PowerShell script will take a bulk list of SIDs and “translate” them into readable Usernames (UIDs).

The PowerShell Script

Save this script as SIDtoUID.ps1. It uses the .NET SecurityIdentifier class to perform the translation locally or against your Active Directory domain.

# Create or clear the output file
Out-File UID.txt
# Loop through each SID in the source text file
foreach ($SID in (Get-Content SID.txt))
{
    # Create a SID object
    $objSID = New-Object System.Security.Principal.SecurityIdentifier ($SID)
    
    Try
    {
        # Attempt to translate the SID to an NT Account name
        $objUser = $objSID.Translate( [System.Security.Principal.NTAccount])
        
        # Append the Username to the output file
        $objUser.Value >> UID.txt
        Write-Host "Translated: $SID -> $($objUser.Value)" -ForegroundColor Green
    }
    Catch
    {
        # If translation fails (e.g., deleted account), keep the original SID
        $SID >> UID.txt
        Write-Warning "Failed to translate: $SID"
    }
}

How to Use It

Create your input: Create a file named SID.txt in the same folder as the script. Paste your SIDs there, one per line.
Run the script: Open PowerShell and execute .\SIDtoUID.ps1.
Check your results: A new file named UID.txt will appear, containing the translated usernames in the same order as your original list.

Why do SIDs sometimes fail to translate?

In the Catch block of the script, we tell PowerShell to just output the original SID if it can’t find a match. This usually happens for two reasons:

Deleted Accounts: The user or group no longer exists in Active Directory, leaving behind an “orphaned” SID.
Connectivity: Your machine cannot reach the Domain Controller to perform the lookup.

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