How to resolve Outlook calendar syncing issues between Desktop and Mobile apps

Calendars & Scheduling KB-359

Summary

This guide helps you troubleshoot and resolve: How to resolve Outlook calendar syncing issues between Desktop and Mobile apps. Follow the steps below to fix the issue.

Quick Tip: Need immediate assistance? 💻 Open a Ticket

Common Causes

It is common for Outlook users to experience a "sync gap" where appointments created on a Windows or Mac desktop application do not immediately appear on the iOS or Android mobile app. This is typically caused by account authentication errors, incorrect folder synchronisation settings, or cached data conflicts within the mobile application.

Quick Fix Steps

Before performing a full account reconfiguration, try these rapid solutions to force a synchronisation cycle:

Restart the App: Completely close the Outlook app (swipe it away from your recent apps) and relaunch it.
Check Connectivity: Toggle Airplane Mode on and off to refresh your network connection.
Manual Sync: On the mobile app, pull down from the top of the calendar view to trigger a manual refresh.

Detailed Instructions

1. Verify Account Connection on Mobile

Often, a password change or security update can put the account into a "limited" state where mail works but calendar syncing pauses.

Open the Outlook app on your mobile device.
Tap your profile icon in the top-left corner.
Tap the Settings (gear icon) at the bottom left.
Select the email account experiencing the issue.
Check for any alerts stating "Account Error" or "Login Required". If found, tap the alert and re-enter your credentials.

2. Reset the Account Cache

If the account is connected but events are missing, the local cache may be corrupted. This process forces Outlook to re-download your calendar data from the server.

Open the Outlook app and go to Settings.
Select the affected email account.
Scroll down and tap Reset Account.
Confirm the reset. The app will restart and begin re-synchronising your folders.

3. Check Calendar Folder Permissions (Desktop)

If you are using a shared calendar or a secondary folder, ensure the calendar is actually stored in the primary Exchange or Office 365 mailbox, as local .pst files do not sync to mobile devices.

Open Outlook on your desktop.
Go to the Calendar view.
Look at the folder list on the left. Ensure your events are saved under the Calendar - [Your Email Address] folder.
If events are saved in a folder labelled "This computer only", they will never sync to your mobile device. You must move these events to your primary cloud-based calendar.

Pro Tip: To move "This computer only" events, simply drag and drop the appointment from the local calendar to the cloud calendar in the desktop sidebar.

Troubleshooting Advanced Issues

Managing iOS/Android System Permissions

If you are using the native Apple Calendar or Samsung Calendar app instead of the official Outlook app, you must ensure the account is authorised at the system level.

iOS: Go to Settings > Calendar > Accounts > [Your Account] and ensure the Calendars toggle is switched On.
Android: Go to Settings > Accounts > [Your Account] > Account Sync and ensure Calendar is checked.

Caution: Avoid deleting and re-adding your account as a first resort. If you have "Local Only" folders or notes, deleting the account may result in the permanent loss of that unsynchronised data.

Checking for Service Outages

If multiple users in your organisation are experiencing the same issue, it may be a Microsoft 365 service degradation. You can check the current status of the Microsoft cloud via the Microsoft 365 Admin Centre or by checking official status pages.

If you have followed these steps and your calendar is still not synchronising, please Open a Ticket and provide your device model and OS version.

Still Having Issues?

Need more help? If the issue persists after trying these steps, please open a support ticket and our team will assist you.

💻 Open a Ticket