Yes you can.
Close all open emails.
Create a new mail, just 1 !
Resize it to about the max of you screen.
Double-click the Title bar to maximize and close it.
Create a new one, it should be maximized now.
If 'something' 'somewhere' gives 'some' error, excpect random guesses or no replies at all. Please specify details.
Free Tip: The F1 Key does NOT destroy your PC! - Marc