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Outlook for Mac keeps asking for password of Office 365 account

Outlook for Mac keeps asking for password of Office 365 account

By Michael Kummer | Last Updated on May 18, 2018

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Many users have reported that Microsoft Outlook for Mac keeps asking for the password of their Office 365 account. Thanks to readers of my blog, we have finally fixed the issue for most users. For others, we have at least a temporary workaround until Microsoft provides a fix.

Outlook: Mail could not be received at this time

Like so many other users, I have experienced this problem in combination with my company’s Office 365-hosted Exchange account. Microsoft Outlook 2016 for Mac would randomly but repeatedly prompt me to enter my username and password. The exact error message reads:

Mail could not be received at this time: The server for the account [account] returned the error “Logon failure: unknown user name or bad password.” Your username/password or security settings may be incorrect. Would you like to try re-entering your password?

Outlook for Mac keeps asking for password of Office 365 account
Mail could not be received at this time
Outlook for Mac keeps asking for password of Office 365 account
Enter your account information

Re-entering the credentials makes the dialog temporarily disappears. Sometimes for a couple of hours and sometimes for a few days. But it always reappeared!

Likely cause: Office 365 modern authentication

I suspect that the issue is related to changes in the authentication mechanism that Microsoft introduced in one of the early version of Outlook 2016.

Outlook for Mac keeps asking for password of Office 365 account
What’s new: Issues are likely related to some of the new features

Microsoft fixed the problem with one of the Outlook updates, but unfortunately, the update did not delete individual Keychain entries. Without removing those entries, the problem keeps reappearing. I had tried deleting some entries but missed a few until one of my readers of this blog provided a complete list of entries you need to delete.

Outlook for Mac keeps asking for password of Office 365 account
Exchange account credentials in Keychain

How to fix the problem (for most users)

Launch the Keychain tool and remove the following Keychain entries:

  • Exchange
  • Microsoft Office Identities…
  • MSOpenTech.*
  • Some “OC” keychain entry that might be unrelated

Thanks to Andy R for providing the solution!

Temporary workaround (for everyone else)

If the above solution did not fix your problem, you might have to disable “autodiscovery” using Apple Script temporarily. To do that, perform the following steps, as pointed out by readers YMX and ITadmin:

  1. Go to Spotlight Search > type Script Editor in the search box
  2. Open Script Editor and enter the commands below
  3. Run this script by clicking on the play icon or by going to Script > Run.
  4. Now start working in Outlook and verify if you get the password prompt for the Exchange account in question.

Depending on the exact version of Microsoft Outlook you are using, you may have to try two different “set background autodiscover” commands;

Option 1

tell application “Microsoft Outlook”
set background autodiscover of exchange account “your email address” to false
end tell

Option 2

tell application “Microsoft Outlook”
set background autodiscover of exchange account 1 to false
end tell

To reenable “autodiscover” run the above command again but use “true” instead of “false.”

Outlook for Mac keeps asking for the password

Sometimes a minor gap in quality control, such as the lack of proper upgrade testing can have annoying consequences. The problem “Microsoft Outlook 2016 for Mac keeps asking for password” has been around for since March of 2016. Microsoft should have addressed this issue a long time ago with a patch. At least, they should have told users how to fix the problem manually.