You can use Numpad-9 and Numpad-7 to rotate on Windows and Ubuntu. The orientation may still be changed with shortcut keys. So there's a way to edit the device's configuration file instead to force it to start-up in Landscape mode. Despite the seemingly easy way to configure this, in practice this didn't work for me. Open the Virtual Device Manager, and click the Edit pencil.
If those answers do not fully address your question, please ask a new question. This question has been asked before and already has an answer.
