Like many it seems, I can't save or use undo? I know about resetting the preferences (no help) and exporting as IDML (just irritating). Any ideas on how to actually solve the issue rather than dance around it? (Will Adobe be offering some kinda compensation for all of us who are paying for a faulty product?) Thanks in advance!
I appreciate your fast reply and apologies for my slow acknowledgement! I was not aware of there being different levels but I had been trying Shift+Option+Command+Control. The problem has passed and not through anything I've done, so I can not take credit here. I'm assuming Adobe CC had fixed whatever this bug may have been. I have bookmarked for your website for future reference.