How can I permanently edit the system path?

Question

I'm writing an installer module and I need to add a value to the system %PATH% variable permanently. How can I modify it from the C# installer code?

Answer 1

Well, that's quite yucky. Modifying the PATH is about as evil a thing an installer could ever do. It has gotten a particularly bad rap because so many uninstallers destroy it, causing very hard to diagnose problems.

I think you'll need to write a custom action that modifies the registry. The system environment is stored in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment, Path value. You should force a reboot to make sure the new setting is effective.

And test the uninstall.

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Seeing your comment to SLaks, use HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths instead.