OS X El Capitan mail folder issue I upgraded my Macbook Pro this morning to Version 10.11, and all my personal mail folders disappeared with up to 24 months of archived and must needed emails.  They still show up on my iPhone 6...and I'm getting iCloud flow between the two.  How do I get them to reappear on my Mac?  Help?
It is a common issue, your data did not disappear. Just go to the tab "Mailbox" in Apple mail and than click "Synchronize". All your mails will be downloaded from the servers they were on.