Why do I keep getting unknown calendar appointments in my microsoft calendar?

Hi Liz Freeman,

This behavior can occur when Outlook is automatically processing meeting requests, or when unsolicited (spam) meeting invites are being delivered directly to your calendar.

What to do (safe approach)

• Avoid clicking Accept, Decline, or Respond on suspicious calendar invites.
• Instead, select the item and Delete it, then use Report > Phishing or Report > Junk if that option is available in your Outlook version.

Disable automatic meeting processing (Outlook for Windows – classic)

In Outlook for Windows, you can stop Outlook from automatically handling meeting requests:

• File > Options > Mail > scroll to Tracking and uncheck: “Automatically process meeting requests and responses to meeting requests and polls.”

Quick security check (recommended)

Review your Microsoft account Recent activity. If you notice sign-ins you don’t recognize, change your password as a precaution.

References:

• Phishing and suspicious behavior in Outlook
• Change how Outlook processes read receipts and meeting responses
• What is the Recent activity page?

If you can confirm whether the same calendar items also appear in Outlook.com (web), I can suggest the next best filtering or cleanup step

Please let me know if this proves useful to you, or if you would like further assistance.

I'm looking forward to your reply.

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Unwanted or unknown calendar appointments are usually caused by spam or phishing meeting invitations that were auto-added to the calendar, or by another app/service that has access to the calendar and is creating events.

To deal with these as potential phishing or suspicious items in Outlook:

1. Treat unexpected meeting invitations as suspicious
   • Phishing and scam messages can include calendar invites that look like normal meetings but are designed to get attention or trick into clicking links or calling phone numbers.
   • Do not click any links or open attachments in unexpected calendar items.
2. Check the sender indicators in Outlook
   • In Outlook and Outlook on the web, look at the meeting invitation’s sender:
     • If a "?" appears in the sender image, Outlook could not verify the sender using email authentication. Be very cautious interacting with these messages.
     • If the sender line shows an underlined “via” tag (for example, ******@contoso.com via suspicious.com), the real sending domain may differ from what appears in the From address. Treat unknown senders with a via tag as suspicious.
   • If these indicators appear and the sender is not recognized, delete the invitation from the Inbox and remove the event from the calendar.
3. Remove the unwanted calendar items
   • Open the unwanted appointment/meeting in Outlook.
   • Choose Decline (if it is a meeting request) and select the option to remove it from the calendar, or simply delete the item directly from the calendar view.
4. Report phishing or scam messages
   • If the calendar item came from an email that is clearly a scam or phishing attempt, report it as junk/phishing in Outlook so similar items are filtered in the future.
   • For tech-support-style scams (for example, events claiming the device is infected and to call a number), report them to Microsoft at the tech support scam reporting page: https://msrc.microsoft.com/report/.
5. Be cautious with any email or calendar item that:
   • Promises rewards, refunds, or urgent account actions.
   • Asks to sign in to view a “document” or “invoice” via a link.
   • Comes from a sender that suddenly shows a ? icon or a suspicious “via” domain.

If the behavior continues, review which accounts and apps are connected to the Microsoft account and calendar, and remove any that are not recognized.

References:

• Phishing and suspicious behavior in Outlook