For some reason, I cannot get the emulator to work correctly. I had try a very simple project but still got a blank screen (Please see below screen capture image). Did I do something wrong? Appreciate for any help.
Welcome.
It appears the emulator's Companion failed to update automatically (as it is supposed to).
While the emulator is working you can update manually.
Help>Update the Companion ; . Follow the directions on the screen to perform the update and reconnect the emulator. You may need to do this kind of update whenever there is a new version of the App Inventor software. The emulator needs to be running when you do this.
I find the open beta emulator works better for me than the old emulator, and it has a newer Companion in it.