Exchange account disappears in Mail after install of Mojave

For me, this issue seems to be resolved with macOS 10.14.2. I had the problem with 10.14.1, and did the workaround of disabling iCloud Keychain, which allowed the exchange account to stay. I tried reenabling iCloud Keychain with 10.14.1, but that would cause the Exchange account to disappear. After updating to 10.14.2, I once again enabled iCloud Keychain, and the Exchange account is still alive, 18 hours later.

I think I may have found a solution online that actually worked.

1. Login to https://outlook.office.com/mail/inbox
2. Click on your initials at the top right corner of the screen and click on my account
3. Click on manage security and privacy
4. Click on Additional security verification
5. Click on Create and manage app passwords
6. Create a new app specific password for Apple and copy the password
7. Then create a new exchange account and click on configure manually and enter that password in.

This seemed to work for me and everything is now stable.

After two days of trying various remedies, while working with Outlook for email (not pleasant), I think/hope I've got my Exchange account stable in Mail (and Calendar and Contacts).

As per my previous post, I rebuilt the inbox, removed accounts completely, tried just email (not calendar, contacts), tried just calendar (not mail, contacts)...all to no avail. I read a few posts in other forums suggesting deleting caches and/or specific control files (e.g. EnvelopeIndex-shm) in the mail system folder, but that didn't work. So I decided to throw caution to the wind and:

-removed ALL accounts from 'Internet Accounts' (I had iCloud, Yahoo and another, functioning Exchange account)

-made a backup of everything in Macintosh HD⁩ ▸ ⁨Users⁩ ▸ ⁨user_name ▸ ⁨Library⁩ ▸ ⁨Mail⁩ ▸ ⁨V6⁩

-deleted everything in Macintosh HD⁩ ▸ ⁨Users⁩ ▸ ⁨user_name ▸ ⁨Library⁩ ▸ ⁨Mail⁩ ▸ ⁨V6⁩

-popped "VIPs.plist" back in the MailData folder (Macintosh HD⁩ ▸ ⁨Users⁩ ▸ ⁨user_name ▸ ⁨Library⁩ ▸ ⁨Mail⁩ ▸ ⁨V6⁩ ▸ ⁨MailData)

Once the inboxes rebuilt themselves I was back where I was a few days earlier–VIPs, flags, etc. all intact. And so far, 48 hours later, I still have Exchange functioning in Mail.

I'm sure there's a more elegant and less heavy-handed way to achieve this but in the absence of such a method it might be worth doing what I did.

If there are any (negative) developments I'll be sure to post.

There is a workaround that has worked for me until they actually fix the issue. Go into your iCloud account and uncheck Keychain. Not sure what the link is between Keychain and this issue but turning it off has allowed my Exchange account to stay active.

I had this problem with an Exchange account used for Calendar. I appear to have got it working again by quitting calendar, deleting Exchange and Office365 related items from Keychain, and adding the Exchange account from System Preferences -> Internet Accounts. The account didn't disappear after 60 seconds and after re-launching Calendar things appear to be back to normal (Exchange data has synced).

Thanks! This eventually worked - I kept having the problem until I uninstalled the problematic exchange account from all my linked devices (phone, ipad, laptop). After that, I removed the "exchange" keys from keychain. Then, I reinstalled the exchange account on all the devices. No problems since.

I had this problem too on Mojave and finally managed to fix it. Like others the Exchange account would mysteriously auto-delete after a few minutes of being created. This only happened when iCloud Keychain syncing was ON AND Contacts syncing with Exchange was on.

I tried lots and lots and lots of things - all the above - and others like trashing half my Library folder! Tore my hair out. This is what finally seemed to work:

0) turned Keychain syncing off on the Mac in question

1) deleted/reset my login keychain and all files in Library/Keychain 

2) deleted everything I could in my System Keychain (except for airport passwords). 

3) deleted every 'certificate' I could in my System Keychain on all my Macs.

I think it might have been the last thing that did it, but when I turned keychain syncing back on, the problem went away,

My conclusion was I had some sort of poisonous certificate in my keychain.

Phew!

This was happening to me as well on Mojave 10.14.3. Simply not syncing contacts on the offending Exchange account fixed this problem for me. Thanks to those that did the work to figure this out!!

yes, the 10.14.4 update completely fixed my issues with exchange account disappearing.

I too have been having this very annoying issue with the 2 machines I updated to Mojave. If you haven't already solved this problem, I saw a solution and so far (10 minutes) my account has remained on my computer.

The solution: go to your iCloud account and uncheck keychain. The iCloud account was listed under mail accounts and so it was easy to find and seems to be an easy fix. I am going to keep it unchecked on one computer and checked on the other to see if this is really the fix (scientist by nature). Good luck.

Thanks for the reply. Tried everything from the linked website and still vanishing into thin air. Only thing that has worked is unchecking Keychain in Icloud and that is such a crappy work around. So frustrating.......

I have been told by my employer IT department that "Apple has indicated that this should be fixed in Mojave version 10.14.4.

Since this is currently only in Beta we have not been able to test it yet. 

Apple has not set a release date for that update at this time, but it looks to be soon"

With that being said, guesses on when 10.14.4 will move from beta to production? Or better yet, does anyone currently have the beta downloaded and use an exchange account with no issue?

I've been having this issue for weeks, I just unticked contacts as you suggested but also calendar as well and so far its the longest Exchange has stayed up!!! Fingers crossed this works, Thanks!

I have exactly the same issue, although it didn't materialise until a few days after installing Mojave. I think the problem started when I tried to add or move an Exchange inbox sub-folder in Mail.

Exchange account simply disappears. No error messages, it just goes. I can re-add, settings are accepted, inbox sub-folders appear, emails appear to start downloading but after a short period (seconds or a minute or two, it varies) the inbox dissappears along with the Exchange listing in 'Internet Accounts'. Other email accounts (iCloud, Yahoo) are fine in Mail and Exchange account is fine in Outlook. All is well on iOS devices.

It's not just the email element, it's the whole Exchange account as Calendar and Contact entries disappear too.

I've tried rebuilding the mailbox and manually deleting all cached messages but it makes no difference.

MacBook Pro Retina, mid-2015; Mojave (10.14).

Whenever I have an Exchange email account that gives me problems on macOS or iOS,

I just manually re-add the problematic account as an IMAP account instead, and that usually fixes the issue(s).