Today I learned that it is possible to set an environment variable that will stay persistent in the machines configuration on Windows.

For example, if I wanted to add c:\flutter\bin to the PATH, I can do the below from an Administrator prompt:

[Environment]::SetEnvironmentVariable("PATH", $Env:PATH + ";c:\flutter\bin", [EnvironmentVariableTarget]::Machine)

Actually, there is a small error with the above, since it uses the PATH from the current process, and actually a better form would be:

[Environment]::SetEnvironmentVariable("PATH", [Environment]::GetEnvironmentVariable("PATH", "Machine") + ";c:\flutter\bin", [EnvironmentVariableTarget]::Machine)

The value of [System.EnvironmentVariableTarget]::Machine is just the string "Machine" so this is also equivalent to the below, which may be easier to type:

[Environment]::SetEnvironmentVariable("PATH", [Environment]::GetEnvironmentVariable("PATH", "Machine") + ";c:\flutter\bin", "Machine")

Make sure its from an Adminstrator PowerShell prompt. If the user doesn't have permission, you'll see the below error message:

Exception calling "SetEnvironmentVariable" with "3" argument(s): "Requested registry access is not allowed."
At line:1 char:1
+ [Environment]::SetEnvironmentVariable("PATH", $Env:PATH + ";c:\flutte ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : SecurityException

Finally, also be aware that it updates only the Machine scope, and does not add this to the environment of the current process.

References:

• PowerShell docs about_Environment_Variables