How can I run PowerShell with the .NET 4 runtime?
PowerShell (the engine) runs fine under .NET 4.0. PowerShell (the console host and the ISE) do not, simply because they were compiled against older versions of .NET. There's a registry setting that will change the .NET framework loaded systemwide, which will in turn allow PowerShell to use .NET 4.0 classes:
reg add hklm\software\microsoft\.netframework /v OnlyUseLatestCLR /t REG_DWORD /d 1
reg add hklm\software\wow6432node\microsoft\.netframework /v OnlyUseLatestCLR /t REG_DWORD /d 1
To update just the ISE to use .NET 4.0, you can change the configuration ($psHome\powershell_ise.exe.config) file to have a chunk like this:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<startup>
<supportedRuntime version="v4.0.30319" />
</startup>
</configuration>
You can build .NET 4.0 applications that call PowerShell using the PowerShell API (System.Management.Automation.PowerShell) just fine, but these steps will help get the in-the-box PowerShell hosts to work under .NET 4.0.
Remove the registry keys when you don't need them any more. These are machine-wide keys and forcibly migrate ALL applications to .NET 4.0, even applications using .net 2 and .net 3.5
Please be VERY careful with using the registry key approach. These are machine-wide keys and forcibily migrate ALL applications to .NET 4.0.
Many products do not work if forcibily migrated and this is a testing aid and not a production quality mechanism. Visual Studio 2008 and 2010, MSBuild, turbotax, and a host of websites, SharePoint and so on should not be automigrated.
If you need to use PowerShell with 4.0, this should be done on a per-application basis with a configuration file, you should check with the PowerShell team on the precise recommendation. This is likely to break some existing PowerShell commands.
The best solution I have found is in the blog post Using Newer Version(s) of .NET with PowerShell. This allows powershell.exe to run with .NET 4 assemblies.
Simply modify (or create) $pshome\powershell.exe.config
so that it contains the following:
<?xml version="1.0"?>
<configuration>
<startup useLegacyV2RuntimeActivationPolicy="true">
<supportedRuntime version="v4.0.30319"/>
<supportedRuntime version="v2.0.50727"/>
</startup>
</configuration>
Additional, quick setup notes:
Locations and files are somewhat platform dependent; however will give you an inline gist of how to make the solution work for you.
- You can find PowerShell's location on your computer by executing
cd $pshome
in the Powershell window (doesn't work from DOS prompt).- Path will be something like (example)
C:\Windows\System32\WindowsPowerShell\v1.0\
- Path will be something like (example)
- The filename to put configuration in is:
powershell.exe.config
if yourPowerShell.exe
is being executed (create the config file if need be).- If
PowerShellISE.Exe
is running then you need to create its companion config file asPowerShellISE.Exe.config
- If
If you only need to execute a single command, script block, or script file in .NET 4, try using Activation Configuration Files from .NET 4 to start only a single instance of PowerShell using version 4 of the CLR.
Full details:
http://blog.codeassassin.com/2011/03/23/executing-individual-powershell-commands-using-net-4/
An example PowerShell module:
https://gist.github.com/882528