if you are getting the “adblock isn’t allowed on youtube” warning
ensure that you’re using firefox and ublock origin (yes, i’m being serious. chrome and every other browser based on it (if you don’t know if your browser’s based on it it probably is) isn’t going to work forever. you’re trying to block ads from a google site on a google browser)
click on the ublock origin icon, go to the settings gears, then go to “filter lists” and click “purge all caches” and then “update now”
if it’s still not working, check the pinned post here about youtube for more info on what you should be doing
this is in the subreddit link but this might be tripping up a lot of people so i want to add that if you have the popular extension “Enhancer for YouTube” check its settings and turn off its adblock
