I used to have rules in my Hotmail account (now outlook.com) that added specific categories to each email I received. I just removed those rules and reorganized my folders and now I don't want several of those categories to be in any message anymore.
If I select an individual message I can click the category link to add or remove individual categories. However, if I select more than one message, the categories dropdown only allows me to add new categories to the selected messages. If you try, the checkboxes appear in an "unknown" state, not as checked or unchecked, but clicking them applies the clicked category to all the selected messages (as a result of trying, I now have extra categories to remove).
I need these removed from thousands of messages, so a one-by-one approach is not feasible. Is there anyway to remove these categories in bulk?