function Get-UsernameFromSid {
    <#
.SYNOPSIS
    Converts a SID to a Username

.PARAMETER SecurityIdentifier
    Identifier to use to find a username
#>

    [CmdletBinding()]
    Param(
        [Parameter(Mandatory = $true)]
        [Alias("SID")]
        [string]$SecurityIdentifier
    )

    $objSID = New-Object System.Security.Principal.SecurityIdentifier($SecurityIdentifier)
    $objUser = $objSID.Translate([System.Security.Principal.NTAccount])
    return $objUser.Value
}