Window not showing
From the Finder (MacOS X 10.15.4), I open a n illustrator Document. The app comes forward and I see a black screen. The "Window" menu tells me that the document is open BUT where? I don't see it (nope, I don't have a second monitor). Clowe the invisible window and the Window menu shows nothing open. Try again, from the finder and again, no windows look opened. Try from Illustrator, File/Open: same thing, another fail. Quit app, relaunch app by launching doc from the Finder. now the file opens as it should. Close file, try again. Back to the black screen. This started happening after this morning's (04/21/2020) update.
try manually resizing the screen