Use PowerShell 2 with .NET Framework 2.0

PowerShell 2 uses .NET Framework's 2.0 by default.

If you use PowerShell 2 and try to import the a module (such as VisioPS) which requires .NET Framework 4.0, you'll get an error like this:

This assembly is built by a runtime newer than the currently loaded 
runtime and cannot be loaded.”

To see what versions any version of Powershell is using, look at $PSVersionTable. For example, below is an example of $PSVersionTable from a Windows 7 machine running Powershell. The CLRVersion indicates which version of the .NET Framework is used and in this case it begins with "2".

Name Value
--- ---
PSVersion 2.0
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0}                         
BuildVersion 6.1.7601.17514
PSRemotingProtocolVersion 2.1
WSManStackVersion 2.0
CLRVersion 2.0.50727.6456
SerializationVersion 1.1.0.1

VisioPS requires a .NET Framework 4.0.

Notice the value or CLRVersion begins with a "2".

In any case, this is a common occurrence with a straightforward solution. You can force PowerShell to start using the .NET Framework 4.0 as documented in this StackOverflow question. The procedure involves creating two small XML files and placing them in the appropriate place.

Here is a small PowerShell script that will automatically create and place the necessary files. Be aware that the script as shown below will overwrite existing .config files.

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

$config_text| Out-File $pshome\powershell.exe.config $config_text| Out-File $pshome\powershell_ise.exe.config

Start PowerShell as an Administrator an then run the script. Then restart PowerShell and examine the value of $PSVersionTable. The value or CLRVersion now begins with a "4". Now your can load VisioPS or any other .NET 4.0 module correctly.

Name Value
--- ---
PSVersion 2.0
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0}                         
BuildVersion 6.1.7601.17514
PSRemotingProtocolVersion 2.1
WSManStackVersion 2.0
CLRVersion 4.0.30319.42000
SerializationVersion 1.1.0.1