PowerShell: Get DLL Info

When you encounter an unfamiliar .dll on your system (or want to confirm exactly which version of a library is installed), PowerShell can pull the embedded metadata out of the file without any third-party tools. The information is the same as what Windows shows in the Details tab when you right-click a file and open Properties.

The Script

Save this as Get-DllInfo.ps1:

param([Parameter(Mandatory)][string]$Path)

function Get-DllInfo {
    param(
        [Parameter(Mandatory)][string]$DllPath
    )

    $fileInfo    = Get-Item $DllPath
    $versionInfo = $fileInfo.VersionInfo

    $dllProperties = [PSCustomObject]@{
        "File Description"  = $versionInfo.FileDescription
        "Type"              = $versionInfo.FileType
        "File Version"      = $versionInfo.FileVersion
        "Product Name"      = $versionInfo.ProductName
        "Product Version"   = $versionInfo.ProductVersion
        "Copyright"         = $versionInfo.LegalCopyright
        "Size"              = $fileInfo.Length
        "Date Modified"     = $fileInfo.LastWriteTime
        "Language"          = $versionInfo.Language
        "Original Filename" = $versionInfo.OriginalFilename
    }

    $dllProperties | Format-List
}

Get-DllInfo -DllPath $Path

Run it by passing a path to any DLL:

.\Get-DllInfo.ps1 -Path "C:\Windows\System32\ntdll.dll"

Output:

File Description  : NT Layer DLL
Type              : Dll
File Version      : 10.0.26100.3775 (WinBuild.160101.0800)
Product Name      : Microsoft® Windows® Operating System
Product Version   : 10.0.26100.3775
Copyright         : © Microsoft Corporation. All rights reserved.
Size              : 2203136
Date Modified     : 4/11/2025 6:47:56 AM
Language          : English (United States)
Original Filename : ntdll.dll

How It Works

Get-Item and .VersionInfo

Get-Item returns a System.IO.FileInfo object for the path. On Windows, .dll and .exe files embed a VERSIONINFO resource block that the OS uses to display file properties in Explorer. PowerShell surfaces this through the .VersionInfo property (System.Diagnostics.FileVersionInfo object).

The properties used in the script:

FileVersion is a free-form string: the VERSIONINFO spec lets the developer put anything there. Microsoft Windows DLLs append the internal build lab name in parentheses, so you get strings like:

10.0.26100.3775 (WinBuild.160101.0800)

The numeric part (10.0.26100.3775) is the actual version. The part in parentheses (WinBuild.160101.0800) is the build lab identifier Microsoft uses internally to trace which build pipeline produced the binary. Third-party DLLs typically omit this and show just the version number.

If you need to parse the version numerically, use FileVersionInfo’s structured fields instead: FileMajorPart, FileMinorPart, FileBuildPart, and FilePrivatePart.

[PSCustomObject] and Format-List

Wrapping the properties in a [PSCustomObject] keeps them in insertion order and lets Format-List print each key-value pair on its own line.

One-Liner Alternative

If you just want a quick look without a script file:

(Get-Item "C:\Windows\System32\ntdll.dll").VersionInfo | Format-List

This dumps everything VersionInfo exposes (more fields than the script above).

Checking Multiple DLLs

To inspect every DLL in a directory:

Get-ChildItem "C:\Windows\System32\*.dll" | ForEach-Object {
    $vi = $_.VersionInfo
    [PSCustomObject]@{
        Name        = $_.Name
        Version     = $vi.FileVersion
        Description = $vi.FileDescription
    }
} | Format-Table Name, Version, @{Label="Description"; Expression={$_.Description}; Width=40}

⚠️ Format-Table drops columns from the right when the terminal isn’t wide enough. Without a fixed Width on Description you may only see Name and Version. The calculated property above caps it at 40 characters to prevent that.

If you want to sort and filter through GUI, use Out-GridView:

Get-ChildItem "C:\Windows\System32\*.dll" | ForEach-Object {
    $vi = $_.VersionInfo
    [PSCustomObject]@{
        Name              = $_.Name
        "File Version"    = $vi.FileVersion
        "Product Version" = $vi.ProductVersion
        Description       = $vi.FileDescription
        "Product Name"    = $vi.ProductName
        Copyright         = $vi.LegalCopyright
        Language          = $vi.Language
        Size              = $_.Length
        "Date Modified"   = $_.LastWriteTime
    }
} | Out-GridView