My mail provider is Yahoo, which has given itself a revamp recently.
I now find that I don't have access to auto-complete my email addresses. If I was going to send an email to Joe Bloggs, when I put the 'j' into the 'to' box all the email addresses beginning with 'j' would appear in drop down window. That doesn't happen any more.
I have tried searching on the Yahoo site and Googling without success.