Melissa, I am confident that you have done everything within InDesign itself, but have you installed other programs or apps recently?
Reset your preferences - Long story
- (Windows) Start InDesign, and then press Shift+Ctrl+Alt. Click Yes when asked if you want to delete preference files.
- (Mac OS) While pressing Shift+Option+Command+Control, start InDesign. Click Yes when asked if you want to delete preference files.
Eugene, Melissa said she already deleted her user prefs.
Maybe she did, maybe she didn't - it was never clarified how the preferences were reset.
The link gives a more detailed and further in depth removal.
Besides, forum posts show up in searches and can be useful to others even if it's not the right answer on this occasion.
Eugene - I did reset my preferences. InDesign wouldn't do it the "normal" way as you suggested, so I went in and deleted the folders. And InDesign still wouldn't co-oporate - but thanks for stating the obvious - did you read the part about I'm an Adobe Certified Instructor and not a beginner?
It's working today. I was having issues with Lightroom not behaving properly yesterday. When I tried to look at it in my Creative Cloud app, that was "broken", too. Everything was working except the Apps screen, which was just spinning like it was loading but wouldn't actually load. This has happened to me before. You can't actually uninstall the CC app - it has a fit and says you still have applications installed. So... I manually re-installed Creative Cloud after I manually re-installed Lightroom and now everybody seems to be working the way they should - for now.
You just said you teach InDesign. And I've met some teachers of indesign that are not ACI.
Glad you have it working and sorry for trying to help...good luck.