I found a fix for 2021
It was my antivirus. Just to clarify, I'm using the free version of Bitwarden but I used to use avast, and the process should be very similar.
First of all, bitwarden not only blocked plutonium but also put some of the files in quarantine. Click on the gear icon at the top and then click on "quarantine." It should show 1 or 2 plutonium files. All you have to do is click on the little circle arrow icon and it will not only restore the file to where it was before, but it will also exclude it from being scanned/quarantined again. This should fix the problem
Whether you're on avast or Bitwarden, it should show you the history of what they blocked. You can click on these and undo the blocking and/or exclude the files that they blocked. You need to make sure that all of the plutonium files are out of quarantine and that they're all excluded. If you need to, create an exclusion for the entire folder located in Appdata/Local/Plutonium.