How to fix Outlook Calendar events not syncing between your desktop, web browser, and mobile phone

Summary

This guide helps you troubleshoot and resolve: How to fix Outlook Calendar events not syncing between your desktop, web browser, and mobile phone. Follow the steps below to fix the issue.

Common Causes

If your Outlook Calendar events are missing or out of date on your desktop, web browser, or mobile phone, you likely have a synchronisation issue between your device and Microsoft 365. This guide walks you through the most effective fixes to get your appointments appearing consistently across Outlook Desktop, Outlook on the Web, and iOS or Android mobile devices.

Quick Fix Steps

1. Check your internet connection on all affected devices.
2. Restart Outlook on your desktop and close the app completely on your mobile device.
3. Sign out of your Microsoft 365 account and sign back in on each device.
4. Verify that you are using the same Microsoft 365 email address on every device.

Detailed Instructions

Outlook Desktop (Windows)

1. Open Outlook and select File from the top menu.
2. Choose Account Settings, then select Account Settings from the dropdown.
3. Select your Microsoft 365 email account and click Change.
4. Ensure Use Cached Exchange Mode is ticked.
5. Click Next, then Finish, and restart Outlook.
6. To force a refresh, press F9 on your keyboard.

If you use Outlook for Microsoft 365, cached mode stores a local copy of your mailbox. Temporarily turning it off and back on can resolve stubborn sync errors.

Outlook on the Web

1. Open your browser and go to outlook.office.com.
2. Sign in with your Microsoft 365 credentials.
3. Select the Calendar icon from the left-hand navigation pane.
4. Refresh the page using Ctrl + F5 (Windows) or Cmd + Shift + R (Mac).
5. Check whether the missing events appear here. If they do, the issue is isolated to your desktop or mobile app.

iOS (iPhone or iPad)

1. Open the Settings app.
2. Scroll down and tap Mail, then tap Accounts.
3. Select your Microsoft Exchange or Microsoft 365 account.
4. Ensure the Calendars toggle is switched on.
5. Open the Calendar app, tap Calendars at the bottom, and confirm your work calendar is ticked.
6. Pull down on the calendar list to refresh.

Android

1. Open the Outlook app on your Android device.
2. Tap your profile icon in the top left corner.
3. Tap the Settings gear icon.
4. Select your email account under Mail accounts.
5. Ensure Sync Calendars is enabled.
6. Return to the calendar view and pull down to refresh.

On some Android devices, battery optimisation can stop background syncing. Go to Settings > Apps > Outlook > Battery and select Unrestricted.

Troubleshooting

Check for duplicate calendars

• In Outlook Desktop, look at the calendar pane on the left. Ensure you are not viewing multiple calendars with overlapping names.
• Uncheck any calendars you do not need to avoid duplicate or conflicting entries.

Verify your default calendar

• When creating a new appointment, confirm it is being saved to your Microsoft 365 calendar and not a local Calendar folder stored only on your computer.
• Events saved to a local folder will not sync to the web or your mobile phone.

Clear the Outlook cache

1. Close Outlook completely.
2. Press Windows key + R to open the Run dialog.
3. Type %localappdata%\Microsoft\Outlook and press Enter.
4. Rename the RoamCache folder to RoamCache.old.
5. Restart Outlook. It will rebuild the cache and resynchronise with the server.

Renaming the cache folder is safe, but do not delete your .pst or .ost data files unless instructed by a technician.

Check Microsoft 365 service status

Occasionally, calendar sync issues are caused by a service outage. Visit the Microsoft 365 Service Health dashboard through your admin portal to confirm there are no active incidents affecting Outlook or Exchange Online.

If you have completed these steps and your calendar events still do not sync across devices, Open a Ticket with our Brisbane support team.

Still Having Issues?