outlook 2016 on Mac - "Mailbox already exists" error.

Anonymous
2016-10-06T05:13:04+00:00

Error "mailbox already exists (0.000 + 0.000 secs)" - and outlook loses connection to IMAP server (shows empty account).

Then, either through manual intervention (clicking on another account and then coming back), or sometimes it just does it by itself, it "rediscovers" my IMAP mailbox and works OK... Until next time (falls over every ?? 30 minutes or so).

Using outlook 2016 on Mac, V15.26.1. This also happened on previous version.

Didnt used to be a problem. Just started about 2 weeks ago with no changes from my end that I am aware of!?! Upgraded to latest Version today. Made no difference.

Advice welcome!

Outlook | MacOS | Legacy Outlook for Mac | For business

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  1. Jim G 134.1K Reputation points MVP
    2016-10-09T16:33:50+00:00

    I would start by verifying that the email account settings in Outlook match the current settings from your email provider. Pay particular attention to security settings.

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  2. Anonymous
    2016-10-14T03:37:50+00:00

    Thanks Jim. All of the account settings are correct, including the security settings. 

    I am getting an error "No mailbox selected (0.000 + 0.000 secs)." and a blank inbox, and then after a while it manages to restore itself, and all my imap messages are visible again.

    I've found someone else with the same problem here http://answers.microsoft.com/en-us/outlook\_com/forum/oemail-osend/outlook-for-mac-2016-mail-disappears/ef54d294-8ebf-462e-879e-da6f11bc1e16

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  3. Jim G 134.1K Reputation points MVP
    2016-10-15T13:53:51+00:00

    Version 15.27 is now available. Please give it a try. Here's how to update:

    The first thing to do is install the recent updates. Make sure your Mac has a working internet connection, then:

    Update Mac OS X. Open the App store and click on the Updates button. Install the updates.

    After, in any Office application go to the Help menu and choose Check for Updates to launch the AutoUpdate app. Let AutoUpdate install updates and then restart your Mac.

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  4. Anonymous
    2016-10-31T03:03:38+00:00

    Problem still persists. I have updated to all the latest versions of the OS and of the Office applications.

    Has anyone got a solution to this?

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  5. Jim G 134.1K Reputation points MVP
    2016-11-01T16:02:17+00:00

    If I were troubleshooting this my next step would be in Outlook, toggle the Sync Status and Sync Errors window on by pressing Command-7 and then Command-8. Then just keep an eye on those windows for a while and see if any traffic going by looks problematic, especially when the problem occurs.

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