Exchange account disappear in the accounts preferences window

I was able to work around my issue.

When using office365, you will need to goto the portal, log in. Then goto my accounts in the top right, then My account. There, goto Security & Privacy on the left pane, then Additional security verification. In the drop down, select Create and Manage app passwords. There you can make an app specific password for Apple Mail. Save it and then copy the password (the button to copy does not work, so select and drag, Control-c) paste the password to text edit.

Then you can add the exchange account to your mac, use microsoft sign-in but use the app specific password instead of your general account password.

So i had a similar issue, while it did not start happening immediately after Mojave upgrade, my mail account just randomly stopped syncing about 24 hours ago, no errors/warnings nothing connection doctor reported all OK

First thing i tried was delete account and re-add, this time i got the shiny oAUTH interface and MFA prompts from Office365 rather than needing device passwords etc and then i got stuck into the same loop as you.

From various googling and reading i have found a potential solution (potential in that it has yet to "delete" my account so far since doing it.)

The trick is do configure manually and use the following internal and external server URL "https://outlook.office365.com/EWS/Exchange.asmx"

I also setup a device password and used that rather than my account password just like i did on older versions of MacOS that did not support MFA from Office365

it sounds like Apple has borked something in the oAuth/MFA routine for Exchange/Office365 accounts - this almost harks back to the original bugs when they started making Google Apps/Suite work with MFA on Mail.app

I chose manual configuration. But didn't get prompted to enter any URL except password. I entered password and this time the account didn't disappear. I think the key is choosing manual for configuration.

Some of my coworkers have the exact same issue, others don't. The configuration for our organization is the same. We use Office 365 with multi-factor authentication. When I disable iCloud on the computers for the people that have the issue their Mail will keep the account. Once you reconnect iCloud and it does a sync the account disappears. The funny thing is that they have it also enabled on their iPhone, iPad, and some people even have it enabled on another Mac. It isn't consistent aside from it's somehow connected to iCloud synching to that specific computer it will remove their exchange account even though the account is present on other devices that have the same iCloud account enabled.

yeah i think they will only show up if you have MFA active and attempt to use your account password instead of an app specific password which will obviously fail and trigger the prompt for server URL's (and ultimately needs you to put in the app specific pass too)

I did not attempt supplying the app specific pass straight away so it could be that would give similar user experience to you as well

I have the same problem, but it only started after I deleted an account and then re-added it. I was wondering if it had something to do with Keychain (as I saw it happen across multiple macs). I turned off keychain on two of my macs and the account was not deleted. If it happens again though, I will try the manual method.

A quick update on my previous try. Turning off keychain seems to have made the biggest difference for me. I was hoping that there was some mechanism to not store the internet accounts in keychain, but have not found a way to selectively do so.

Same issue for me. I have done manual config and now the Exchange persists in the internet accounts. However I'm not getting very reliable syncing between Mail and Exchange.

Unread count on iOS (my phone) and web UI doesn't change in response to actions I take in Mail.

All very sketchy right now.

Hi Karlavecunk, I am seeing the same thing with my Exchange account. After I add the account by signing in and authenticating it, the account just disappears within a minute or two. This is a new issue that started after installing MacOS Mojave.

Noticed the same issue.

Same issue here. Started with MFA. Account disappears in about 2 minutes. Adding manually does not work. I am dead in the water.