If you've ventured into the world of PowerShell extensions and modules, and more specifically, that world, targeted at SharePoint, then you have probably run into this error before.

Import-Module : Could not load file or assembly 'file:///C:\cjvandyk.SharePoint.PowerShell.dll' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded. At line:1 char:14+ import-module <<<< .\cjvandyk.SharePoint.PowerShell.dll + CategoryInfo: NotSpecified: (:) [Import-Module], BadImageFormatException + FullyQualifiedErrorId : System.BadImageFormatException,Microsoft.PowerShell.Commands.ImportModuleCommand

This error is thrown by PowerShell when you are using the Import-Module cmdlet to import a PowerShell module (redundant, isn't it?) that was built using the .NET Framework 4.0.  The ugly error looks like this:

If you're trying to use that module on a SharePoint system, the odds are that the server does NOT have the 4.0 version of the Framework installed.  You can easily confirm this by simply checking the sub folders under the C:\Windows\Microsoft.NET\Framework location.

In the above example, you can see that 1.0, 1.1, 2.0, 3.0, 3.5 and 4.0 are all installed on the server.  If you find that 4.0 is NOT installed, you can quickly install it following this guide.

Once it's installed you only have one more thing left to do.  By default, PowerShell will run under the 2.0 Framework.  We need to force it to default to the 4.0 Framework and only revert back to 2.0 if it doesn't find what it's looking for in 4.0.

That is easily done using a .config file for the PowerShell executable.  Browse to the C:\Windows\System32\WindowsPowerShell\v1.0 location.

You may not have the two .config file on your system.  If you don't, you need to create them manually.  Name the files exactly the same as the .exe files, but with a .config extension at the back.  Create them as text files, but you will need to show extensions from your Folder Options in Windows Explorer in order to get rid of the .txt extension.  The two config files should be named "PowerShell.exe.config" and "PowerShell_ise.exe.config".  The content of the two files is a simple XML snippet that simply points PowerShell to default to 4.0 and fallback to 2.0.  Copy and paste the following snippet into the .config files.

<?xml version="1.0"?>
<configuration>
  <startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0.30319"/>
    <supportedRuntime version="v2.0.50727"/>
  </startup>
</configuration> 

Now when you restart PowerShell, attempting to load your module should yield no errors (if your module is compiled correctly and valid), and you should be able to implement the functionality from the module without any problem.

Enjoy
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