How do I stop massive unwanted spam invitations from appearing on my calendar?

For a personal Outlook.com account, there is currently no setting that completely prevents unsolicited meeting invitations from being placed on the calendar; Microsoft Q&A identifies this as an ongoing service-side issue, so the available actions are mitigations rather than a guaranteed block.^1^

Handle incoming invitations safely

1. Do not open links or attachments in the invitation.
2. If the invitation menu offers Report, select Report junk or Report phishing, and then remove the item. Availability varies by Outlook client and calendar-item type.
3. If Report is absent, delete the invitation without interacting with its contents. Classic Outlook only gained calendar-item reporting in Microsoft 365 Version 2512, build 19530.20000 and later; this does not guarantee that every Outlook.com web item has the same command.^2^
4. Avoid sending a response when removal offers that choice. Responding confirms that the address is active.

Unfortunately, clearing the existing entries may remain a manual task. The available sources do not document a safe bulk-removal procedure for Outlook.com spam invitations.

Apply the available mitigations

Block recurring senders or domains

In Outlook.com:

1. Select Settings → Mail → Junk email.
2. Under Blocked senders and domains, select Add blocked sender.
3. Enter the sender address or, if the spam consistently uses one domain, that domain.
4. Select OK, then Save.

This moves future email from the listed sender to Junk, but it might not prevent Calendar from processing every meeting request. Spammers also commonly change or conceal sender addresses, limiting the effectiveness of blocking.^3^^4^

Turn off “Events from email” only if these are extracted events

If the entries are travel, delivery, reservation, or similar events automatically extracted from ordinary email—not actual meeting invitations:

1. Open Calendar in Outlook.com.
2. Select Settings → View all Outlook settings.
3. Open Calendar → Events from email.
4. Clear Automatically add events to my calendar from email, or disable the affected event categories.

This setting controls events Outlook detects inside email; it does not stop genuine meeting requests sent as calendar invitations.^5^

If this is a work or school account

Ask the Microsoft 365 administrator to implement external meeting-request mail-flow filtering with exceptions for trusted domains. Because this can block legitimate external invitations, it should be tested with an allowlist. The administrator can also review mailbox AutomateProcessing; the relevant Q&A guidance says None keeps invitations in the Inbox until the user responds, whereas AutoUpdate can place them on the calendar tentatively.^6^

These Exchange Online controls are not available to an administrator of a personal Outlook.com/Hotmail account.

Escalation for personal Outlook.com

Only Microsoft can provide complete service-side prevention for personal Outlook.com accounts. Sign in and vote or comment on the Outlook calendar-spam request in the Microsoft Feedback Portal. You can also use Help in Outlook.com to contact support and provide screenshots and sample sender details; support may document or escalate the abuse, but there is currently no guaranteed account-level fix reported by Microsoft Q&A.^1^

References

1. Spam invitations in my calendar - Microsoft Q&A
2. Unable to report meeting items as junk in classic Outlook
3. Filter junk email and spam in Outlook | Microsoft Support
4. Receiving email from blocked senders in Outlook.com
5. Calendar settings in Outlook on the web | Microsoft Support
6. How to stop auto accepting invites from External Senders - Microsoft Q&A