Since Windows 95, and earlier, Windows has suffered from a miserable editor for environment variables. Something most users need to do at some point, usually when something is going wrong and they are on with support, should not have to decode a line of cryptic characters and %TOKENS%. Linux, I expect to be a bit rough, but not a “consumer” OS. I even considered writing a Control Panel app once, but lost interest.
Enter Rapid Environment Editor. It shows the User and System environment vars in a separate tree, allowing you to individually edit each entry in the PATH, for example. AND it shows in red the segments that are INVALID! Duh! Click save, and you are done.
I just donated $10. Highly recommended.