Apologies if this has been discussed to death. I just did a clean Catalina install on my 2012 MBA, and my MS Office Home & Student 2019 purchase doesn't want to be recognized on MS site. I had it legitimately running on Mojave and diligently deauthorized my MBA in iTunes. In retrospect, I should have done the same in MS apps - but I did not. MS site has a record of my purchase and shares the key, but downloads of MS office are either pushing me to 365 or of no help to sign in. I did a full TM backup before the clean install - is that of any help to bring the Office back, or is my only solution to pay the evil MS again?