@kgalyen said in Extension Manager and Plugins Manager not working on Mac: if disabling them using these managers disables them for the current session or only once sketchup is restarted? Also, disabling them keeps the plugins files in the plugins folder correct? Disabling is persistent across sessions but you can load plugins temporarily not extensions. Disabling does not remove plugins/extensions. They are renamed to prevent loading and enabling/loading temporarily will restore their original names.

Well, as you see in my edit comment that method is another way to do it. But I suggest you post in the thread I provided, so that the author can guide you. There may be some other factor causing the fail.