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why are there unknown names listed in Groups in outlook calendar

Brooks M 15 Reputation points
2026-01-06T15:29:13.0933333+00:00

There are new, unknown names that are suddenly showing in outlook calendar Groups. As this is a personal account, there is no work related admin that would have impacted the setup. I cannot find a mechanism to delete these unknown groups on either the desktop or web outlook applications

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  1. J A 0 Reputation points
    2026-04-22T19:09:51.7733333+00:00

    I had the same issue. Here is what worked for me.

    When viewing Outlook Mail or Outlook Calendar on my laptop, you'll see in the leftmost column there are 8 icons (Mail, Calendar, People, To do, Word, Excel, PowerPoint, More apps). Click on "More apps" and you'll see "Groups" and "OneNote". Click on Groups.

    Then you should see, in the column just to the right of the icons mentioned above, the Groups to which you belong.

    Click on the Group name that you want to delete.

    Under the name, you'll see icons for "Mail," "Calendar," and "Members". Click on Members, and then the Settings icon.

    Then you should see some options, the last of which is "Delete" the group. Click on Delete and you will no longer see that group.

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  2. Marcelo Mendoza 10,685 Reputation points Independent Advisor
    2026-01-06T16:59:03.75+00:00

    Hello Brooks,

    Thank you for reaching out with your concern about the unexpected group names appearing in your Outlook calendar I understand how confusing it can be to suddenly see unfamiliar groups listed especially when you are using a personal Outlook account and there are no organizational administrators who could have modified your setup. It is completely understandable to feel concerned when changes appear without warning and there is no obvious way to remove them as this can make it seem like something is misconfigured or beyond your control.

    In many cases these unknown group names are related to Outlook automatically synchronizing shared calendars or retaining legacy group associations that were previously connected to your account through calendar invitations, subscriptions or Microsoft services tied to your Microsoft account such as Teams Free or shared family calendars. Outlook can sometimes keep these references even after the original sharing relationship is no longer active.

    To address this you can try switching to Outlook on the web navigating to the calendar view and reviewing the shared calendars section for any entries that can be deselected or removed. Signing out of Outlook on all devices, clearing the browser cache for Outlook on the web and then signing back in may also help refresh the calendar data and clear out outdated group entries. It can also be helpful to review connected services and permissions in your Microsoft account settings as removing old calendar or group connections there often causes the unknown names to disappear once Outlook completes a fresh sync.

    Could you let me know if these unknown group names appear the same way on both the desktop and web versions of Outlook and across all your devices or if they only show up in one specific app?

    I hope this answer is helpful if you have further questions feel free to reply back

    Regards,

    Marcelo

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  3. AI answer

    2026-01-06T15:30:20.8966667+00:00

    The presence of unknown names in Outlook calendar groups can occur for several reasons. One common cause is that these names may be associated with a Microsoft 365 group that you are a member of, but which is hidden from your Outlook client. If the group is hidden, it may not appear in the usual lists, but you can still see its members in calendar views.

    To address this, you can check the following:

    1. Verify Group Membership: Ensure that you are a member of the group in question. You can do this by checking the group details in the Exchange admin center if applicable.
    2. Hidden Groups: If the group is hidden from Outlook clients, you can unhide it using PowerShell commands if you have access to that functionality. Run the command Get-UnifiedGroup -Identity <group name> | FL HiddenFromExchangeClientsEnabled to check its status and Set-UnifiedGroup -Identity <group name> -HiddenFromExchangeClientsEnabled:$false to unhide it.
    3. Viewing Group Calendars: Make sure you are accessing the group calendar correctly. Instead of opening it from the address book, try expanding the "All Group Calendars" section in the calendar view to see if the group appears there without the unknown names.

    If these unknown names persist and you cannot find a way to remove them, it may be worth reaching out to Microsoft support for further assistance.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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