My InDesign has frozen, and doesn't let me open up or create new documents. I have tried force quitting and it's telling me that the request cannot be processed due to open selection or warning dialog?? I have no idea what that means, but it's literally not letting me do anything because that window keeps popping up.
If Force Quitting in the Activity Monitor won't work you will have to shut down your computer either by holding down the power button or unplugging it. When you restart completely sign out of Creative Cloud. When you open inDesign again try a new document to see if the problem is in the doc you were working in when ID became unresponsive.