How do you transfer ownership of a shared calendar when the owner leaves the company?

Question

How to transfer ownership of shared calendar when the user who created it leaves the company?

Answer 1

Hi @Patrick, Jan,

Thank you for posting your question. In Microsoft 365, calendar ownership is associated with the mailbox, not with a standalone calendar object. Because of this design, there is no automatic way to transfer ownership once the original owner leaves the organization. The appropriate resolution depends on the current state of the user account.

Since this is a business‑managed environment, there is limited action an end user can take directly. I recommend contacting your IT administrator and asking them to assist based on the applicable scenario.

If the original owner’s account is still accessible, the IT administrator can sign in to that account and transfer ownership on your behalf. Only the calendar owner can assign another owner. This can be done using the Outlook desktop client by following these steps:

• Open Calendar
• Right‑click the shared calendar and select Properties
• Go to the Permissions tab and select Add
• Choose the user who should become the new owner and click OK
• Set the Permission Level to Owner
• Click OK, then Apply to save the changes

Please note that only an existing owner of the shared calendar can grant Owner permissions to another user.

Additionally, if the employee has already left the organization, it is recommended to convert the mailbox to a shared mailbox. When a mailbox is converted to a shared mailbox, the calendar is retained permanently, administrators can assign Owner permissions for this shared mailbox using Exchange Online PowerShell, and the calendar is not deleted or subject to the 30‑day deletion period.

If the user account was already permanently deleted and the mailbox was not converted to a shared mailbox, the mailbox and its calendar are permanently removed after 30 days. In this case, ownership cannot be transferred. The only available recovery option is to export the calendar as an ICS file within the 30‑day retention window and import it into another mailbox as a new calendar.

To export the calendar as an ICS file, go to Settings > Your app settings > Calendar > Shared calendars > Calendar publishing, select the calendar you want to export, set the permission level to Full details, and then click the ICS link to download the required file.

After that, you can import the new calendar file. In the Outlook web access, click Calendar> Add calendar> From file, and them choose the ics file you exported

I hope this provides enough clarity and helps you stay inform with your current situation.

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Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.   

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Answer 2

Outlook calendars don’t support a literal “ownership transfer” of a user’s primary calendar. When the person who shared the calendar leaves, the usual approach is to ensure others have the access they need and, if necessary, recreate or re-share the calendar under an active user’s account.

For Outlook on the web / Microsoft 365 shared calendars, use these options:

1. If the original owner is still present (account not yet deleted)
   • Sign in as the owner (or an admin acting on their behalf) and share the calendar with the required people:
     1. In Outlook on the web, go to Calendar.
     2. Select Share.
     3. Choose the calendar to share.
     4. Enter the names or email addresses of the people who need access.
     5. Choose the appropriate permission level.
     6. Select Share.
   • Each recipient can then add the shared calendar via Add calendar → Add a person’s calendar and selecting the owner.
2. If the original owner has left and the account is disabled but still exists
   • An admin can sign in or otherwise access the mailbox and re-share the calendar as above so others retain access.
   • If the calendar is already shared, users can remove and re-add it using a supported Outlook client to upgrade it to the new shared calendar model if needed:
     • Delete the existing shared calendar from their view.
     • Use a later version of Outlook (including Outlook on the web) to Add a person’s calendar and select the former owner’s mailbox.
3. If the original owner’s account will be removed
   • Before deleting the account, an admin should:
     • Decide who will “own” the calendar going forward.
     • Have that person create a new calendar under their own mailbox.
     • Manually recreate key events or export/import events if appropriate.
     • Share the new calendar with the same audience using Share in Outlook on the web.
   • Once the new calendar is in place and shared, the old account can be removed according to organizational policy.
4. Using shared mailboxes or resource mailboxes
   • For long-term, role-based calendars (for example, team or department calendars), consider:
     • Creating a shared mailbox or resource mailbox.
     • Using its calendar as the “team calendar,” shared with all relevant users.
   • This avoids tying the calendar to a single employee who may leave.
5. Upgrading existing shared calendars to the new model (if behavior is inconsistent)
   • If a shared calendar isn’t behaving as expected after the owner leaves or after re-sharing, users can:
     1. Delete the shared calendar from their profile.
     2. Re-open it using a later version of Outlook (including Outlook on the web). This upgrades the shared calendar if access was explicitly granted.
   • If access was granted via the Default (My organization) group or a security group, the copy won’t be upgraded and may need to be re-shared explicitly.

There is no direct “transfer owner” button; the practical solution is to re-share or recreate the calendar under an active account (often a shared mailbox or a manager/role account) and ensure everyone adds that calendar instead of the former employee’s.

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References:

• Share calendars in Outlook on the web
• Calendar sharing in Microsoft 365