How to fix issue of a Mac Outlook Shared Calendar not showing past events older than 1 year.

Hi @trevelan

Thank you for posting your question in the Q&A Forum.

We understand it can be frustrating when older events in a shared calendar don’t appear as expected. 

Sometimes, a shared calendar may appear differently for the owner and the person it is shared with. The synchronization behavior on the Mac client can vary compared to the owner’s primary view. This often relates to how the app caches calendar data and other factors, such as the permissions granted. 

You could try the following steps to refresh the data: 

• Remove and Re-add the Shared Calendar: This forces a fresh synchronization and rebuilds the local cache. 
• Check the Permission Level: Verify the access granted by the calendar owner (e.g., Reviewer, Editor, or Delegate), as different permissions can occasionally affect data visibility. 
• Check Outlook on the Web (OWA): If older events are visible in OWA, it confirms the full data set exists on the server, and the issue is likely related to synchronization on the Mac client. 

If older events still don’t appear, your administrator could contact Microsoft Support for further assistance with server-side sync logs. Additionally, we highly encourage submitting feedback directly through the Outlook app (Help > Feedback) requesting enhancements for shared calendar history, your input helps the development team prioritize improvements. 

Please let us know if you have any questions. 

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