New, Blizzard had an uninstall and install that keeps your addon’s, eliminates errors, and makes repairing your game problem easy.
I had a problem, with one character. Vuhdo worked on all my other characters but not on my druid, it sent up error messages. I had removed the addon that did not play well with others. But for some reason it’s effects stayed on my druid.
I installed and reinstalled the game and was amazed at the excellent process Blizzard has now for doing this. Took a few minutes. Solved my problem. My game had slowed down also.
I was having a problem completing quests. The GM’s were kind and helped. Even though I was ready to delete the toon and felt like quitting the game. Afterward I decided to reinstall my game, but hated to do that because of all the problems involved in redoing my UI. However I got all my addons back with no errors or problems in them.
I am grateful Blizzard does listen to us and is always making the game better. Even when we are raunchy.