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Working with PowerShell Extensions: PSSnapins and Modules

PowerShell’s true strength lies in its extensibility. Beyond built-in cmdlets, administrators can load PSSnapins and modules to manage diverse technologies such as Exchange, SQL Server, VMware, and SharePoint. While PSSnapins were the original extension method, modules—introduced in v2—are now the preferred approach, offering portability and autoloading in v3 and later. Managing extensions involves discovering, loading, and inventorying them, as well as handling conflicts and autoloading preferences. Understanding these mechanisms is essential for efficient administration.

PowerShell ExtensionsPSSnapinsModulesAutoloadingGet-ModuleImport-Module

~2 min read • Updated Dec 21, 2025

1. One Shell, Many Extensions


There is no product-specific version of PowerShell. Shortcuts like “Exchange Management Shell” simply run PowerShell.exe with arguments to autoload modules, scripts, or snap-ins. Administrators can combine multiple extensions into a single custom shell.


2. PSSnapins vs. Modules


  • PSSnapins: Introduced in v1, written in .NET, packaged as DLLs, require installation and registration.
  • Modules: Introduced in v2, portable, often copied between systems, support autoloading in v3.

3. Loading and Autoloading


Before v3, extensions had to be loaded manually or via profiles. In v3, modules stored in $env:PSModulePath autoload when their commands are invoked. PSSnapins do not support autoloading.


4. Discovering Extensions


  • Get-PSSnapin –Registered: Lists installed snap-ins.
  • Get-Module -ListAvailable: Lists available modules in PSModulePath.
  • Remote discovery: Use Get-Module -PSSession to list modules on remote machines.

5. Loading Extensions


  • Add-PSSnapin: Loads a snap-in.
  • Import-Module: Loads a module (autoloads if in PSModulePath).

6. Discovering Additions


Use Get-Command -Module to list commands added by an extension. Extensions can also add providers, viewable with Get-PSProvider.


7. Managing Extensions


  • Remove-Module: Unloads a module.
  • Remove-PSSnapin: Removes a snap-in.
  • Get-Module / Get-PSSnapin: Lists loaded extensions.

Be aware of command name conflicts. The most recently loaded command takes precedence, but fully qualified names (e.g., ActiveDirectory\Get-ADUser) or -Prefix can resolve collisions.


8. Autoloading Preferences


The variable $PSModuleAutoLoadingPreference controls autoloading:


  • All: Default, autoloads modules on first use.
  • ModuleQualified: Autoloads only with qualified names.
  • None: Disables autoloading.

Conclusion


PowerShell extensions are the backbone of advanced administration. By mastering discovery, loading, and management of modules and snap-ins, administrators unlock the full potential of PowerShell to manage diverse platforms and technologies.


Written & researched by Dr. Shahin Siami

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