Q: Mail not working after update OS X 10.10.4 and IOS 8.4

I upgraded to OSX 10.10.4 on 2 iMac and a MacBook Air and to IOS 8.4 on an iPhone and iPad.  Problem occurs on just one of the iMac - all other devices are fine, but Mail just shows spinning beach ball on the one iMac.  Tried copying the full Mail database folder ~/Library/Mail/V2 from one of the devices that was working, but that made no difference.  Any ideas on possible fix?

Same problem :-(

If you can’t send or receive email on your Mac - Apple Support

Exactly the same here with my iMac on 10.10.4 - as soon as I updated - smtp fails. I can send on MBP on 10.10.3 - I could send on the iMac right up till the point I updated. This is quite a common issue with this update. On to Apple Chat support - they are baffled - as though this is the first they've heard of it - it was an issue in the beta. Then chat support cut out. Hey ho.

How do I restore my machine from Time Machine?

Same problem on my MacBook Pro (late 2014) with 8GB RAM and 128SSD.  Mail Freezes.  Albeit I have 20+ email accounts in it, all imap.

Only workable solution was to install Thunderbird (free) which is flawless.  My iPhone and iPad mail work fine. (so far....)

Note:  When I first installed the update it worked FINE.  Then I (properly) exited MAIL, and rebooted.  That's when I had the problem.  I had to force quit and I DID send the report when I force quit'd

Same problems here (Macbook -- retina, 2015). All smpt accounts in Mail have stopped working after installing 10.10.4. Iphone mail app working just fine though.

I'm unable to receive emails at all. Funny thing is that i'm able to send out emails.

The issue started directly after upgrading to 10.10.4

I keep getting the error "Failed to authenticate with google"

My MBA 11 (Mid 2011) currently running Yosemite, and I haven't upgraded to 10.10.4 ( it still showing 10.10.3) - this morning while I working on pages, a dialog box appears asking me to close iTunes, and I did so. Now my mail apps are spinning for hour and hour and asking me to setup a new mail account. I CAN NOT OPEN MY MAIL...please HELP

Hmm, came back to the problem machine this morning and Mail worked when I started the app - no spinning beach ball thankfully.  Machine was on overnight, but without Mail running.  Perhaps the issue I was experiencing was to do with synching between machines and completing upgrade of other machines resolved the problem.  It sounds as though the SMTP issue that others are reporting is a separate problem.

Brian, same for me. Fired up my iMac this morning to find Mail is now working again. Most strange.

Same problem as well. Neither IMAP nor SMTP work today after upgrade to 10.10.4 done yesterday. Just stopped working, with no changes done on my side. Tried removing and adding all accounts back, but to no avail.

I had this problem, with Gmail and Exchange mail accounts.

The way I fixed it was to go into preferences for Mac Mail, and then Accounts.  Then for each mailbox, go to the advanced tab and tick "Automatically detect and maintain account settings".

I then saved the configuration changes and restarted Mail and my accounts started working again.

If this works for you, please post to the forum.

I had that checked already. I tried uncheckimg, restarting, then checking it and restarting. No change.

I had a triangle icon next to the mailboxes that weren't working.  With the changes I suggested, the triangles went away and the mailboxes started working again (although most of my Exchange mail is missing).  Do your mailboxes have triangle icons next to them, or is it something different?