I need to delete a calender pernamently

Hello glen martin,

Thank you for posting to Microsoft Q&A. 

I can certainly understand how annoying it is to have a "ghost" calendar that keeps reappearing seconds after you delete it. This usually happens because the calendar is being re-synced from a server or a specific subscription link that hasn't been broken yet. 

To remove it permanently, please follow these steps: 

1. Delete via Outlook Web 

• Log in to Outlook.com and go to the Calendar view. 
• Right-click the unwanted calendar and select Delete or Remove. 

2. Remove from Internet Calendars (Desktop App) 

If the calendar returns, it is likely an ICS or internet-based subscription.

• In the Outlook desktop app, go to File > Account Settings > Account Settings. 
• Click on the Internet Calendars tab. 
• If the calendar is listed there, select it and click Remove. This stops Outlook from "re-downloading" the data every time you sync. 

If the steps above don't work, it may be due to the type of calendar: 

• Built-in Calendars (Birthdays/Holidays): These are features rather than traditional folders and cannot be deleted. To hide them, go to Settings (Gear Icon) > Calendar > View on the web and uncheck "Turn on the birthday calendar." 
• Shared or Team Calendars: If this was shared with you by a colleague or is a company resource, you cannot delete it permanently unless you are the owner. In these cases, you should right-click and select "Remove" or "Unsubscribe" instead. 

I hope this finally clears that calendar from your view! Please let me know if you have any other questions. 

Best regards, 

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In classic Outlook for Windows, what happens next depends on what kind of calendar it is and why it keeps coming back.

1. Confirm it is not the primary calendar

• The primary Outlook calendar cannot be deleted. If the Delete option is grayed out, it is the primary calendar. In that case, only the items inside it can be deleted:
  1. Go to Calendar.
  2. Select View.
  3. In Current View, select Change View > List.
  4. Click in the item list and press Ctrl+A to select all items.
  5. Right‑click the selection and choose Delete.

2. If it is a shared, team, group, or SharePoint calendar These are copies in the profile. To remove them so they stay gone:
3. In Calendar, in the Folder Pane, right‑click the calendar.
4. Select Delete Calendar (or Delete Group for a group calendar).
5. Confirm with Yes. Only the local copy is removed; the source calendar remains intact on the server.
6. If a specific calendar item keeps reappearing If the problem is a single meeting/appointment that returns after deletion, it may be a corrupted calendar item. In that case an Exchange admin must:
7. Run in Exchange PowerShell:

      Set-Mailbox <name_of_affected_mailbox> -CalendarVersionStoreDisabled $true
   

8. Wait about two hours for cache to expire (or, on-premises only, restart the Information Store service or remount the database, which causes service interruption).
9. Delete the problematic calendar item (recommended via the MFCMAPI tool).
10. Re-enable logging:

        Set-Mailbox <name_of_affected_mailbox> -CalendarVersionStoreDisabled $false
    

If the entire calendar folder itself is reappearing, verify whether it is a shared/group calendar being auto-added from the server; in that case, removing it as in step 2 is the supported method.

References:

• Delete a calendar in Outlook
• Can't delete calendar items in Outlook