Shared calendar not syncing

Summary

This guide helps you troubleshoot and resolve: Shared calendar not syncing. Follow the steps below to fix the issue.

Common Causes

Problem

A calendar shared with you by a colleague isn't syncing or showing events, or changes to a shared calendar aren't appearing for others.

Symptoms

• Shared calendar doesn't show any events
• Events appear for you but not for others
• Calendar shows “Last synced” a long time ago
• You can see the calendar in the list but it's empty

Solutions

Step 1: Verify Calendar Sharing Permissions

The organizer needs to share correctly:

1. In Outlook, go to Calendar → Share.
2. Ensure permissions include at least the “Reviewer” level.
3. If they shared only “Free/Busy”, you won’t see details.

Check your access level:

1. In the Calendar view, locate the shared calendar in the left sidebar.
2. Right‑click and choose “Properties” or “Permissions”.
3. Confirm your permission level.

Step 2: Ensure the Calendar Is Added

Check your calendars list:

1. In Calendar view, look at the left sidebar.
2. Verify the shared calendar is listed (it will display the owner’s name).
3. If it’s missing, add it:
   • Click “Add calendar” → “Open shared calendar”.
   • Enter the person’s name or email address.
   • Select them and click “OK”.

Step 3: Force a Sync

Outlook Desktop (Windows):

1. Go to Send/Receive → Send/Receive All Folders.
2. Wait for the sync to complete.
3. If needed, close and reopen Outlook.

Outlook for Mac:

1. Choose Tools → Sync Settings and click “Sync Now”.
2. Alternatively, close Outlook and reopen it.

Outlook Web (O365):

1. Open Outlook Web in a private or incognito browser window to rule out cached data.
2. If the issue persists, sign out of your Microsoft 365 account and sign back in.

Outlook Mobile Apps (iOS/Android):

1. Pull down on the calendar view to trigger a manual refresh.
2. If the calendar still does not appear, toggle the account off and on in Settings → Accounts.

Step 4: Check for Duplicate Calendars

1. Examine the left sidebar for multiple entries of the same calendar.
2. If duplicates exist, right‑click the extra entry and choose “Remove”.

Step 5: Remove and Re‑Add the Calendar

1. Right‑click the shared calendar and select “Delete” or “Remove”.
2. Confirm the removal.
3. Re‑add the calendar using the steps in Shared Calendar Permissions Guide.

Step 6: Verify Permissions Again

If events still aren’t showing, the organizer should:

1. Right‑click their calendar and choose “Share”.
2. Ensure you have been added with at least “Reviewer” permissions.
3. Confirm the permission level is not set to “Free/Busy only”.

Step 7: Check for Delegates

1. Go to File → Account Settings → Delegate Access.
2. Confirm you are listed as a delegate.
3. Ensure delegate permissions include Calendar access.

Step 8: Troubleshoot Outlook Desktop Issues

1. Close Outlook.
2. Press Win + R, type %localappdata%\Microsoft\Outlook, and press Enter.
3. Delete the contents of the RoamCache folder.
4. If sync issues persist, consider renaming your local Offline Outlook Data File (.ost). Outlook will rebuild this file upon restart, which can resolve corruption causing sync delays.
5. Restart Outlook.

1. Press Win + R, type control, and press Enter.
2. Navigate to Mail → Show Profiles.
3. Select your profile, click Properties → E‑mail Accounts → Repair.
4. Restart Outlook.

Step 9: Check Internet Connectivity and Microsoft 365 Service Health

Sync issues are often caused by network interruptions or Microsoft 365 service outages.

1. Verify your internet connection is stable by opening a website in your browser.
2. Check your firewall or proxy settings to ensure they are not blocking Outlook's connection to Exchange Online.
3. Visit the Microsoft 365 Service Health dashboard to check for any active incidents or advisories affecting Exchange Online or Outlook.

Step 10: Microsoft Teams and Microsoft 365 Groups Calendars

If you are accessing a shared calendar through Microsoft Teams or a Microsoft 365 Group:

1. Ensure you are a member of the specific Team or Group associated with the calendar.
2. Open the calendar directly in Outlook Web to verify if it syncs there. If it works in the web app but not the desktop app, the issue is likely local to your Outlook installation.
3. For Group calendars, confirm the group owner has not modified sharing permissions or removed you from the group.

For the Calendar Owner

If others can’t see your calendar:

1. Share it correctly: Calendar → Share → Add person.
2. Select “Reviewer” or a higher permission level.
3. Click Send – recipients must accept the invitation.
4. Ask them to confirm they have added the calendar.

Common Permission Levels

• Free/Busy time – Only shows whether you’re free or busy.
• Limited details – Shows subject and location.
• Reviewer – Can read all details.
• Delegate – Can read and respond to meetings.

Need More Help?

If the calendar still does not appear, permissions are correct but events are missing, you have tried re‑adding multiple times, or you are dealing with a departmental/team calendar, please Open a Ticket. You may also find the following articles useful:

• Calendar invite not showing
• Using Outlook Calendar and Scheduling Meetings

Still Having Issues?