How do I restore the prompt to send updates only to added or deleted attendees?

When adding or removing attendees from an Outlook meeting invite, you should receive a prompt offering:

• Send updates only to added or deleted attendees
• Send updates to all attendees

If this prompt isn't appearing, choose your Outlook version below for the correct fix.

Classic Outlook desktop app

1. Open the classic Outlook desktop app (not New Outlook or Outlook on the web).
2. Go to File → Account Settings → Account Settings.
   
3. Under Email, select your account and click Change….
4. Click More Settings, then open the Advanced tab.
5. Under Microsoft 365 features, uncheck Turn on shared calendar improvements, click Apply, then OK.
   
6. Close Outlook completely and reopen it.
7. Repeat steps 1–5, re-check the box, click Apply, then OK.
8. Close and reopen Outlook again.
9. Open a meeting invite, make attendee changes — the prompt should now appear.

This workaround addresses a Microsoft-acknowledged issue affecting certain builds of Outlook before version 2305 when shared calendar improvements are enabled.

New Outlook and Outlook on the web

These versions do not offer the prompt. Microsoft designed the update process to function automatically:

• If only attendee changes are made, updates are sent only to added or removed attendees.
• If other details change (such as time or location), updates are sent to all attendees.

This is expected behavior in New Outlook and OWA. If you prefer to manually choose who receives updates, use the classic Outlook desktop app.