Dear Bonolgirl55,
This has been a very frustrating experience - and I know there are many others out there dealing with this same problem. I have had several email and live chat conversations with the INDesign team about this. They have not yet solved the problem (they are reportedly aware and working on a fix for future update), but we did find two workarounds to the problem.
First workaround is to export as IDML files and open that way. That is a maddening solution, you will find, and still does not allow you to UNDO or use the program to its maximum efficiency. It does help you prevent complete loss of your work however.
Second workaround -- assuming you are using a Mac -- was to create a completely new Mac User on your computer, logout of your current user, then login to new user and reopen InDesign there. When I did that, InDesign had no problems at all. It worked fine. The issue with that, of course, is that you have to make sure your files and graphics are all copied over to new user Documents file, or or otherwise accessible from a shared drive somewhere. This solution allowed me to use InDesign without any of the Save / Save As / Undo issues -- but obviously undercut workflow productivity between Adobe programs and with other files, email, etc. as I was essentially cut off from my normal desktop work environment and lacked easy toggle between Mac Users.
I am afraid that I have no other solution to offer, and I don't know when Adobe will figure this out. My problem ONLY applies to InDesign (I am a Creative Cloud subscriber). It's been very unpleasant and annoying.