I recently received a reply to an email which froze my Apple Mail. I couldn't delete it or do anything and after re-booting a couple of times when I reopened Mail my account details from an old service provider appeared and I lost everything in my current mail (and no, I hadn't backed up with Time Machine!). I am up and running again but the system is running at a concerningly slow pace (I am not being impatient - something is very wrong!) and am fearful this will loss of data and shutdown will happen again. Any advice please?