Suddenly any new document I tried to make opened up as black in Photoshop. I also couldn't make a new layer to try and simply put something on top o it. This happens both in CC2017 and CC2018. It started happening suddenly and for no apparent reason. I discovered (by trial and error) that if I used the legacy "new document" panel, the problem goes away. (This is the case for both CC2017 and 2018) I tried to report it as a bug, but am unable to report any bug at all on the Adobe bug-reporting page. Just wondering if anyone else had this issue. I don't like the newest "new document" window, so I don't care if I can't use it. But I was wondering if this is a known issue.
Sounds like one of those issues where resetting Preferences will be the quickest solution.