InDesign CC: "File does not exist, you do not have permission, or the file may be in use"
I am a new subscriber to Creative Coud, previously working in InDesign desktop versions. I tried to open some files I'd worked on a few weeks ago and now am getting the error message: "File does not exist, you do not have permission, or the file may be in use by another application."
I've restarted CC, restarted INDD, tried to open from the icons for the files as well as using file/open. Nothing works and I need to get these files in today. So far, this Creative Cloud subscription thing has been kind of a bust, but I'm hoping someone out there knows how to solve this. Didn't see any previous answers. [edit - no answers until AFTER I posted this]
SOLVED: I think it's a Dropbox sync issue. INDD just spins, then gives the error, then spins some more then opens the file in Dropbox. [I would have deleted this whole question, but can't find the option to do that.]