I am suddenly getting 2 sent emails in my sent folder which was working fine for last 2 years its only started in last 7 days.

I am using Mac Mail running OSX El Capitan 10.11.4 on both iMac and mac book pro.

I have gone in mail/preferences/mailbox behaviours and de selected "show sent messages on server" but this then deletes all sent messages.

This doesntbhappen when i send messages from any iOS device.

Please help

Perry