Calendar Problems

Fix Outlook Calendar Not Syncing with iPhone or Webmail

Chanuka Geekiyanage Sep 28, 2026 869 views

Question details

Users are experiencing issues where their Outlook Calendar fails to sync across devices, specifically with iPhones and webmail clients.

How to Fix Outlook Calendar Not Syncing with iPhone or Webmail

Product: Microsoft Outlook
Device & OS: not provided
Scenario: Attempting to synchronize calendar events across multiple devices after an Office update, using IMAP or Exchange ActiveSync accounts.
Observed behavior: Calendar changes made in Outlook do not reflect on the iPhone or webmail. For IMAP accounts, calendars are stored locally, and for Exchange accounts, sync breaks after specific version updates.

Before you start

Verify your active internet connection on all devices and ensure you know your email account type (Exchange, IMAP, or POP) before modifying sync settings.

Solution 1Recommended

Check Account Protocol and IMAP Folder Limitations

Determine if your account is using IMAP, which natively restricts calendar syncing across devices, and identify local-only folders.

The IMAP protocol is designed to synchronize email messages only. It does not support syncing contacts or calendars natively.

When using an IMAP account (like Shaw or Rogers) in Outlook, your calendar is often stored in a folder marked 'This PC Only', meaning those entries will never push to your iPhone or webmail.

Open Account Settings

Launch Microsoft Outlook, click on 'File' in the top left corner, and select 'Account Settings' followed by 'Account Settings' from the dropdown.

Verify Account Type

Look at the 'Type' column next to your email address. Note whether it says 'IMAP' or 'Microsoft Exchange'.

Check for Local Folders

Navigate to the Calendar view in Outlook. Look at the folder list on the left pane to see if your primary calendar is labeled with '(This PC Only)'.

Check Account Protocol and IMAP Folder Limitations

IMAP Limitation: If your account is IMAP, this lack of calendar sync is an expected protocol limitation, not a software error. You may need a third-party sync tool or an Exchange account.

Solution 2

Revert to a Previous Stable Office Update

Roll back your Office installation to an earlier version (such as 2312) if a recent update broke Exchange ActiveSync compatibility.

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Frequently Asked Questions

Why is my Outlook calendar marked as 'This PC Only'?

When you add an email account using the IMAP protocol, Outlook creates a local data file to store items that IMAP cannot sync, such as calendars, contacts, and tasks. These items are marked 'This PC Only' to indicate they exist solely on that specific computer.

How can I sync an IMAP calendar with my iPhone?

Because IMAP cannot sync calendars natively, you must either use a third-party synchronization utility, switch to an Exchange-based email service (like Outlook.com or Office 365), or sync your local Outlook calendar using iCloud for Windows.

Can an Office update cause my calendar to stop syncing?

Yes. Software updates occasionally introduce bugs or alter how protocols like Exchange ActiveSync communicate. If synchronization worked fine on an older version (like 2312) but fails after an update, it is likely a version-specific issue that should be reported to Microsoft.

Outlook & Email Problems