Reset corrupt Outlook delegate permissions

  • Applies to: Exchange Online, Outlook on the web, Outlook for Windows, New Outlook for Windows, Outlook for Mac

Summary

Reset corrupt Outlook delegate permissions to resolve DelegateCollectionUpdateFailedException and Failed to update delegateCollection errors that prevent users from adding, changing, or removing Outlook delegates. To resolve the errors, reset the mailbox owner's delegate collection, restore each delegate's calendar permissions, and verify the delegate access.

Symptoms

  • Outlook or Exchange Online PowerShell returns DelegateCollectionUpdateFailedException or Failed to update delegateCollection.
  • Adding, changing, or removing a delegate fails for the mailbox owner's primary calendar.

Cause

The delegate collection that stores a mailbox owner's delegates is corrupt. Outlook and Exchange Online PowerShell both use this collection when you add, change, or remove a delegate, so the same error occurs in both.

Resolution

Use these steps when a user can't add, change, or remove an Outlook delegate because the mailbox delegate collection is corrupt.

  1. Record the current calendar permissions. You must restore each delegate after the reset.

    Get-MailboxFolderPermission -Identity owner@contoso.com:\Calendar

    For syntax and parameter details, see Get-MailboxFolderPermission.

  2. Reset the delegate collection on the mailbox owner's primary calendar.

    Remove-MailboxFolderPermission -Identity owner@contoso.com:\Calendar -ResetDelegateUserCollection

    The reset removes corrupt delegate data and changes existing delegates to Editor permissions. For details, see Remove-MailboxFolderPermission.

  3. Restore each delegate with Set-MailboxFolderPermission. Add CanViewPrivateItems only for delegates who should see private calendar items.

    Set-MailboxFolderPermission -Identity owner@contoso.com:\Calendar -User delegate@contoso.com -AccessRights Editor -SharingPermissionFlags Delegate

    Set-MailboxFolderPermission -Identity owner@contoso.com:\Calendar -User delegate@contoso.com -AccessRights Editor -SharingPermissionFlags Delegate,CanViewPrivateItems

Verify the resolution

Run Get-MailboxFolderPermission again. Confirm that each delegate has Editor access and that SharingPermissionFlags contains Delegate. Then have the mailbox owner add or remove a test delegate in Outlook.

More information

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