My InDesign CS6 was working. My Creative Cloud subscription lapsed a few months ago. Today, InDesign 6 won't work. A window to subscribe to Creative Cloud pops up. I renewed my subscription and now InDesign CS6 is asking for a serial number. I don't have one. How do I go about getting InDesign 6 to work without having to upgrade my OS? Thanks.
Try logging out of the CC Desktop app and then log back in again and let it update the subscription status.