Hi, welcome to LQ!
#1 and MOST troublesome) I experience unpredictable crashes, When typing an email I am unable to recapture that which I wrote.
You'll need to help us in helping you; which software are you using
for writing e-Mails, what is crashing? The app, the desktop, the whole
#2) without warning the "back" button disappears. it is sometimes there and sometimes not.
The back button of which software? We can't see what you see...