have been trying Astroberry out via VNC (ie headless). All working fine, however today I attached an external monitor and keyboard directly to my Pi4 and could not get the desktop to come up - got the screen in he attached image. Even when this screen was on the monitor, I could still log in via vnc from my PC.

I reflashed the latest image - same result
I reflashed the latest image and did all the updates - same result
I then flashed Raspian, did its updates - this worked perfectly with my monitor, I then installed Astroberry in to Raspian, the monitor then showed the same pic.
At this point I gave up, has anyone any suggestions?