macOS Catalina is the End of the Road for InDesign CS6
As the saying goes, time waits for no one. Nor does it wait for our favorite software programs. This week, Apple is released macOS Catalina (10.15), which fully ends support for 32-bit apps like InDesign CS6. So if you’re one of the folks holding on to CS6 (or any earlier version of InDesign) to avoid becoming a Creative Cloud subscriber, it’s essential that you do not upgrade to Catalina.
Personally, I find it very helpful to keep a copy of CS6 on one of my computers for reference when InDesign is acting strangely to see if the behavior I’m seeing is new or not.
You can read this post by Steve Werner for more details on Catalina ending support for 32-bit apps.