Q: Has any one found that their mail inbox was emptied?  This seems to have happened today.

I sent a message to myself and it came through.  I am also getting new emails.  I tried to index the mail box using the instructions from Apple but the files it says to access I cannot find using their instructions for Mountain Lion.  Not sure if El Capitan is set up different. 

I deleted the Envelope Index files in V3 and it appeared the mails rebuilt but  the inbox messages are still missing from two days ago.  Not sure where they went. Thanks for your help though.