@ReyCuba
Delete plutonium.exe and plutonium.new.exe and download a new copy of the launcher here: https://cdn.plutonium.pw/updater/plutonium.exe
Then place the new exe anywhere you want: on your desktop or in your game files folder for example and run it.
The update process will start and you won't have anything more to do next times, only run plutonium.exe and it'll automatically update
If this still doesn't work then reply by saying what your antivirus is (even if it is disabled or has exclusions)