I have the same problem only on my 2 email accts on my new Iphone 6 which is 2 days old. Autocomplete does not remember all my email addresses only a handful... I troubleshooted each email acct several times over the last 2 days, adding, deleting, adding, changing specs, and autocomplete does not fully work. Even called godaddy to troubleshoot. Does it take time for autocomplete to remember the email addresses for my accts? BTW, the email accts work fine in terms of sending and receiving emails... fyi, the 2 email accts I have on this new phone are yahoo and a godaddy acct... Any suggestions or advice appreciated.