Photoshop open but no windows visible

I've searched and tried all the suggestions for similar issues. Nothing has worked yet.

Occasionally, after PS has been open for awhile, I will come back to it and nothing happens. No windows display, no open projects, no tool palettes, nothing. I can click Open > New, it will show options for the new canvas, but as soon as I hit ok, nothing. Resetting workspaces, changing window arrangement, right clicking in the Dock > Show All Windows, all do nothing. Someone suggested un-clicking application frame so I thought that might fix it, but it was greyed out. So that makes me think something is locking up the App frame and not displaying it properly.

I can also open Preferences and see those, but no workspace, no canvas, nothing. The only fix is to quit the app, and start over. Not terribly detrimental, but it still shouldn't be happening. Running the latest Mac OS X 10.12.15, with the latest update for Photoshop CC.