Microsoft Exchange – Meeting requests keeps updating not invited person

This one looks strange the first time you see it: someone who was never originally invited keeps receiving meeting updates anyway. In the case that led me to write this post, a recurring meeting was auto-forwarded to a private mailbox and then accepted from that private address. Even after the forwarding rule was removed, the updates kept coming.

What is really happening

The problem is usually not an Exchange transport loop and not a still-active forwarding rule. The real issue is that the forwarded recipient effectively became part of the meeting conversation when their acceptance was processed by the organizer.

Once that external or alternate address is represented as an attendee on the organizer side, future updates continue to go there because Outlook and Exchange are simply honoring the meeting membership they know about.

Fix

The real fix is on the organizer side:

• Ask the meeting owner to open the meeting series.
• Remove the unintended external or private address from the attendee list.
• Send the updated meeting again.

If the meeting is recurring, make sure the organizer checks the full series and not only one occurrence.

Why deleting the forwarding rule is not enough

Removing the mail flow rule or Outlook forwarding rule only stops new forwarded copies from being created. It does not automatically remove an address that was already incorporated into the meeting's participant state.

Good practice going forward

If users regularly forward meeting requests to private mailboxes or shared mailboxes, this symptom can come back. A few practical guardrails help:

• Avoid accepting forwarded meetings from alternate personal addresses.
• Prefer delegate access or shared mailbox permissions instead of mailbox-level forwarding for calendar workflows.
• If the symptom affects a recurring series, always review the organizer's copy of the meeting.

This is one of those issues where the best troubleshooting step is simply understanding the behavior. Once you know the organizer owns the authoritative attendee list, the symptom makes a lot more sense.