Outlook Calendar not auto-accepting Bookings appointments

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I have tried everything I can think of and still no luck. Any help would be greatly appreciated.


A group of our university academic advisors created a Bookings calendar to allow students to book time with various staff members. All staff members are able to be booked appropriately using the same services. Of course, multiple staff are assigned to provide each services. For all staff members except one, the appointments are automatically added to their calendars. One of them is forced to manually accept any appointment that is booked with her. Considering she can have 15+ appointments booked per day, it is a considerable time suck and annoyance to have to go through this with each. I have combed through every Bookings setting and compared the problematic person's account to everyone else's. Everything matches. 


Has anyone else experienced this and, if so, what solution did you come up with? Is there some deep dive setting in Outlook that I am missing? I have also searched at length online and haven't come up with a comparable issue from anyone else. 




5 Replies
We're having the same issue now as well, where one account will auto-accept a Bookings event, and another will not. Did you end up finding any solution to this?
Can you please confirm if the user for whom this does not work have any delegates configured on their calendar? Depending on the settings, the event might get forwarded to the delegate and might remain unaccepted on the original recipient's calendar.
We have set up "read and manage" permissions on the mailbox from the 365 Admin center for the user, to allow it to be opened as an additional mailbox for the user(s). However I don't see any forwarding of the event outside of the mailbox.

If this is the cause, is there a way to retain the "auto-accept", but still keeping the "read and manage" permissions for the mailbox?
best response confirmed by davisjr (Microsoft)

We finally found a fix for this. Because of how long it takes for Exchange account updates to go through, I'm not completely sure which step fixed the issue.


For us the issue happened because of what people are calling "ghost delegates" in an account, where a previous delegate isn't being removed correctly. Note that we still have delegate access on the mailbox itself (which includes the calendar), but we have removed delegates from the calendar account itself (details in these steps):


  1. Remove all delegates from the Calendar itself, except for these two:
  2. In Powershell connect to Exchange online: `Connect-ExchangeOnline`
  3. Run `Get-Mailbox -Identity "[EMAIL]" | Get-MailboxPermission`
    This will show any delegates you have on the mailbox itself. It's fine to keep these.
  4. Run `Get-MailboxFolderPermission -Identity "[EMAIL]:\Calendar"`
    This will show any calendar delegates you have on the mailbox itself. I think that this needs to just contain "Default" and "Anonymous". Even though we had "ghost delegates", they didn't show up here.
  5. At this point, we created and cancelled a Bookings event. Only the cancellation message showed the following, which indicated that we must still have a "ghost delegate"
  6. Run `Remove-MailboxFolderPermission -Identity "[EMAIL]:\Calendar" -ResetDelegateUserCollection`
    This cleans up the mailbox, and I believe it was this step that removed the "ghost delegate"
  7. (optional) For some reason we didn't have "Anonymous" as one of the delegates, so we ran this as well:
    `Add-MailboxFolderPermission -Identity "[EMAIL]:\Calendar" -User Anonymous -AccessRights None`

As a result of these changes, when a booking is created, it is now auto-accepted. And when it is cancelled, we no longer get the message about cancellation being "sent to your delegate(s)", so I hope these steps also help someone else.

@Kevin260 and @davisjr

I had forgotten that I posted it here, so never came back to update this thread. My bad.

My colleagues and I went back and forth with Microsoft premier support for over two months trying to find a resolution. We tried soooo many things.

We removed all delegates of all types via an automated process multiple times, but one kept reappearing no matter how many times it was removed. Once we figured out how to remove that one delegate entirely (manually), the issue was resolved. Unfortunately, the colleague that I worked with is no longer part of our organization and there isn't any detail noted in the original ticket about how they made this happen. If there was, I'd gladly share.

I wish you the best of luck. I do remember that once we got that sticky delegate removed and things started working properly, even Microsoft Premier Support staff couldn't explain why that had done the trick.