Why are random uninvited meetings getting put on my calendar?

If you are receiving random uninvited meetings on your calendar, it could be due to a few reasons:

1. Direct to Calendar Invitations: Some organizations use mail flow rules that automatically add meeting invitations directly to calendars without sending them to the Inbox. This can happen if the sender is authorized to send such invitations. You might want to check with your IT department if such rules are in place.
2. Meeting Requests Misrouted: In some cases, meeting requests may not appear in your Inbox but instead go to other folders, such as Deleted Items. This can happen if you do not have a mailbox delegate set up or if there are issues with how Outlook is processing these requests.
3. Spam or Phishing Attempts: If the meetings are related to spam (like Bitcoin scams), it could be that your email address is being targeted by spammers who are sending out meeting invitations indiscriminately.

To stop these random meetings:

• Adjust Mail Flow Rules: If you have control over mail flow rules, consider modifying them to prevent unauthorized meeting invitations from being added directly to your calendar.
• Check Your Inbox Settings: Ensure that your Outlook settings are configured to route meeting requests correctly to your Inbox.
• Report Spam: If these meetings are spam, report them to your email provider and consider blocking the senders.

You may also want to consult your IT support for further assistance in managing your calendar settings and filtering out unwanted invitations.

SPAM Calendar Events - Update 2025-12-05 - Still an ongoing issue. No update from Microsoft on a general solution.

If your organization has a Microsoft Defender for Office 365 subscription, there are steps your IT Admin can take to mitigate the impact:

https://techcommunity.microsoft.com/blog/microsoftdefenderforoffice365blog/strengthening-calendar-security-through-enhanced-remediation/4456876

If you are in an IT Managed environment, there are Mail Flow Rules that your IT Admin can implement that will block all external Calendar invites (and allow for specific exceptions):

https://learn.microsoft.com/en-us/answers/questions/5558001/how-to-prevent-calendar-invites-from-external-sour

Hi @Danica W,

Thank you for posting your question in the Microsoft Q&A forum.

I understand you're dealing with an issue where unwanted or random meetings (including spammy invites) are getting added to your Outlook calendar.

Here are suggestions you can try to troubleshoot:

1. Check your calendar settings

Your Outlook might be set to automatically accept meeting invites. To change that:

• Open Classic Outlook > go to File > Options > Calendar
• Under Automatic Accept or Decline, click Auto Accept/Decline and then uncheck “Automatically accept meeting requests and remove canceled meetings”

2. Check your inbox rules and filters

You might have created (or unknowingly accepted) rules or filters that are forwarding or automatically processing these invites. Review any rules you have in Outlook:

• Go to File > Manage Rules & Alerts.
• Check for any rules that might automatically accept or categorize meeting invites.
• Delete or adjust any rule that looks suspicious or unnecessary

 3. Block and report spam senders

• If you get a spam invite, right-click the email > choose Junk > Block Sender
• Use the Report button to flag it as phishing

 4. Contact your IT admin

If you’re using Outlook as part of Office 365 or Microsoft Exchange, it's possible that your IT department has set up policies that allow certain invites to be added automatically or that need to be adjusted. Check with them to see if they can apply stricter controls on what types of invites are allowed. If needed, they can submit a support ticket through Microsoft 365 admin center for further assistance.

Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution. 

I hope this information is helpful. Please follow these steps and let me know if it works for you. If the issue persists, please share a screenshot of the field codes for the problematic cell so we can help further.

Thank you for your patience and your understanding. If you have any questions, please feel free to reach out. 

I'm looking forward to your reply. 

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@Danica W

Microsoft is aware of the problem but there is currently no fix. There are no Rules you can create or settings you can change in the Outlook client that will stop these SPAM Calendar Events.

https://learn.microsoft.com/en-us/answers/questions/5597205/prevent-pfishing-calendar-items

Hal Hostetler MVP-Outlook MVP Volunteer Moderator Oct 26, 2025, 12:21 PM

FWIW, this issue has been reported to Outlook Engineering, they are aware of the problem, and are investigating it.