I deactivated and reactivated. Didn't solve the problem. Had the issue once before when upgrading to Mavericks. Vague recollection that there was an issue with confused mac address. Can get the correct one via Terminal/ifconfig en1. But don't know what to do with that. By now I have 3 versions of license.txt files in my /Applications folder. Knowing what to do with those would help too.