Exchange account disappears in Mail after install of Mojave

there is no option for me for Additional security verification.

After latest update 10.14.4, has anybody tried to verify if it started working?

I am on 10.14.2 and I am having this issue right now. It is exactly as everyone stated. It was stable until I removed my Office365 account from from one of my macs, i also have an iCloud account on my macs as well. But 10.14.2 hasn't solved it. I issue i am having is that it works for a short period of time, actually a little more specific as soon as i tried sending an outbound email, (Mac Mail app on my desktop) it remained in my outbox. When i checked the outbound server for my Outlook365 account had disappeared and then shortly thereafter the accounts uninstalled across all my desktop devices (not my mobile ones). I finally had to re-instal Outlook on my Desktop for now. IOS on iPhone 10 is working fine.

Exactly the same problem here too. I have tried to re-add the exchange account, already ~12 times, but every time it just disappears from the list of accounts. One time, I deactivated calendar, reminders, contacts, etc, and just kept mail checked during the initial setup, which resulted in the account last for a couple of days, but then it disappeared again. Serious issue. I have started to use Outlook, since this is a serious interruption.

Yeah, I tried the same today for the company 365 account, didn't work. Same story, after a few minutes the account disappears. I use all the apps, not just calendar.

This is getting silly, has anyone bothered to submit a bug report?

Ooops! Apparently I spoke too soon. Once again the Microsoft Outlook Exchange account has disappeared. I have removed all Outlook and exchange addresses from Keychain and unchecked Keychain in Preferences>iCloud, closed Mail and re-started the computer. Any updates for solving this issue?

Thanks, Johan. I just found a few more suggestions on MacRumors: https://forums.macrumors.com/threads/exchange-account-keeps-deleting.2143129/

My Exchange account has stayed visible and apparentlyh stable for a record 10 minutes after doing the following:

1) When setting up the account check only Mail and Calendar. Instructions for adding Contact synching later are detailed on the page

2) The method for disabling keychains described below turned up a couple of things that hadn't showed up before when I just typed "outlook" or "exchange" in the search window. What came up didn't match the result in bold below, but I deleted it anyhow, and so far so good:

• Open Keychain Access (spotlight search is fastest)
• On the left-hand side, chose All Items
• In the Keychain Access search bar in the upper right, search for exchange
• In the results below, select all items that have com.apple.account.Exchange.oath-### and Delete them
• Quit Keychain Access and go Preferences --> Internet Accounts and re-add the Exchange accounts

Fingers crossed!

Any more updates on this? Still no luck for me and experiencing the same as everyone else. So freaking annoying as this is a work account for me as well and, man, do I not want to have to use Outlook.

I disabled Keychain, and the problem was resolved, but that disables an important function, so I think a better workaround is to just unselect "contacts" when adding the account. Contact seems to be causing the bug. I can still select Mail and Calendar.