New outlook can't retrieve calendar events from teammates after converting shared mailbox to an account

Question

New outlook can't retrieve calendar events from teammates after converting shared mailbox to an account

Thomas Jost Jakobsen 0

We are experiencing an issue where users suddenly can't view the calendars of the people in their nearest team according to the organization hierachy when using New Outlook. This happens after converting a shared mailbox to an account in Settings -> Accounts -> Shared with me. The reason behind converting the shared mailbox is to receive live update count on unread mails in those shared mailboxes.

If they try to open the calendar of any in their team, they get this error: User's image

Microsoft call this "teammates calendars" in the Add calendar option of New Outlook Calendar as shown on the picture below. Those are the only ones affected. Other calendars that have been manually added are not affected by the shared mailbox convertion.

User's image

Disabling this option does not resolve the issue. A temporary workaround seem to be to remove and re-add the calendars of those in your team. After that the calendars can be retrieved, however this stops working as soon as the new outlook client is restarted or reloaded in any way.

Have anyone experienced this issue and hopefully found a way to resolve it? Because at the moment it seems like a dilemma of having to choose between being able to see an updated unread email count on shared mailboxes or seeing the calendars of your teammates.

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2 answers

Your answer

Answer 1

We're seeing the same issue. It seems to be a mix between the following settings

"Show teammates' calendars"
shared mailboxes that are converted to behave as account** (especially if the shared mailbox has the "Show teammates' calendars" turned on)
"Allow offline access to email, calendar, and people" option.

We have noticed that the issue is often resolved if "Show teammates' calendars" is turned off and None of the users shared mailboxes are converted to behave like an account (all shared mailboxes only behaving as a shared folder). But, Shared mailboxes that aren't converted to behave like an account are practically useless and unusable, so most users have decided to use OWA for the calendars they can't access rather than change their shared mailbox settings.
We have a ticket in with Microsoft for this issue but that ticket is still being worked.

**For more context on what I mean by shared mailboxes converted to behave like a shared folder vs behaving like an account, see https://support.microsoft.com/en-us/outlook/sharing/manage-shared-mailbox-settings-in-new-outlook - particularly the section about "Add a shared mailbox as an account in new Outlook"

Answer 2

Anonymous

Hello @Thomas Jost Jakobsen

I would like to first clarify that this is a user‑to‑user support forum. Moderators here are not Microsoft Support, so we don’t have backend access or the ability to perform escalations.

I have tried reproducing this behavior on my end, but "Teammates calendars" continue to load correctly even after converting a shared mailbox to an account.

To help narrow this down, could you please provide:

The New Outlook version/build used by the affected users.
Whether the issue occurs only in New Outlook for Windows or also in Outlook on the web (OWA).

User's image

In the meaning time, please try these basic steps:

Update New Outlook to the latest version.
Test whether the same calendars open successfully in Outlook on the web.
Start Outlook in Safe Mode: https://support.microsoft.com/en-us/office/open-outlook-in-safe-mode-f394c2ee-b2af-e97a-64ee-35cd24414811
Reset the New Outlook app (Settings > Apps > Outlook (new) > Advanced options > Repair/Reset).
Repair your Office: https://support.microsoft.com/en-us/office/lifecycle/repair-an-office-application
Clear cached credentials: Close Outlook completely, then go to Control Panel > Credential Manager > Windows Credentials, remove any entries related to Outlook or Microsoft Office, and finally restart Outlook and sign in again.
Create a new Outlook profile: https://support.microsoft.com/en-US/Outlook/create-an-outlook-profile
Disable Auto-mapping via Exchange PowerShell

Please try these methods and let us know if the issue persists. Also, please share a screenshot of your Outlook build information, as it may help with further investigation

Looking forward to your reply

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Thomas Jost Jakobsen 0 Reputation points

2026-07-07T13:08:38.5666667+00:00
It appears that auto-mapping is the cause of this. Im just adding the other steps below as documentation of what have been tested before coming to the conclusion of auto-mapping causing this.

Using Exchange Powershell i tried testing with a shared mailbox where i removed permissions and re-adding full access permission with automapping set to false. When the shared mailbox was re-added manually, calendars could still load.

Just to confirm i then removed permissions again and re-added with automapping $true, and suddenly the issue returned of not being able to retrieve calendar objects.**

Curent version on clients with issue:**

Microsoft Outlook Version: 1.2026.623.400

Client Version: 20260626009.06

WebView2 Version: 149.0.4022.98 (Stable)

2. Test whether the same calendars open successfully in Outlook OWA

The calendar opens fine in OWA, though in OWA the account convert is not even an option.

3. Safe-mode

Safemode tested with olk.exe --safe as the outlook.exe /safe shared in the link is for the safemode for classic Outlook4. Repair and Reset

Neither repair or reset resolved the issue.

Cache clearing and profile

any crendential cache related to outlook, OLK or office removed and restarted. Did not resolve
Anonymous

2026-07-07T13:42:47.4466667+00:00

Thank you so much for the feedback, the thorough testing, and for documenting every step so clearly @Thomas Jost Jakobsen . I really appreciate you taking the time to share your results and refining the solution.

I am glad to hear that disabling auto-mapping is working as a solution for now. Please feel free to monitor the situation for a few days, and don't hesitate to reach back out if the issue returns or if you need any further assistance.

If you found my answer helpful in pointing us in the right direction, I would greatly appreciate it if you could upvote or mark the response as the answer. This will help other users in the community who might run into the exact same issue.

Thank you again.