Shared Outlook calendars do not always update instantly. They sync on intervals, and the local Outlook cache can fall behind the server. A manual sync or cache rebuild usually brings stale calendars current.
Does this affect you?
Use this for Outlook for Microsoft 365 and Outlook.com on Windows, Mac, or the web when a shared calendar is accessible but changes are not appearing reliably.
Force Outlook to sync the calendar
Start with a manual refresh.
- Select the shared calendar in the calendar list.
- Open Send/Receive.
- Click Send/Receive All Folders or press F9.
- Wait for the progress indicator to finish.
- Check the shared calendar again.
- If needed, right-click the calendar and choose Refresh, or close and reopen Outlook.
Rebuild the local cache
Use this when desktop Outlook stays stale but the server copy is correct.
- Open File > Account Settings > Account Settings.
- Double-click the account.
- Note whether Cached Exchange Mode is enabled.
- Turn it off, finish the wizard, and restart Outlook.
- Turn Cached Exchange Mode back on and restart again.
- Wait while Outlook rebuilds the local calendar data.
More control
Compare with Outlook on the web
Open the shared calendar in Outlook on the web. If it is correct there but not in desktop Outlook, the issue is the local cache.
Check permissions
Ask the calendar owner to confirm your permission level. Low permission levels can limit details or behave inconsistently.
Shared reminders may differ
Reminders on shared calendars do not always behave like reminders on your own calendar. Add yourself as an attendee to critical events if reminders matter.
Allow brief server delays
Right after the owner changes events, wait 10 to 15 minutes and sync again before rebuilding everything.
Sources
- Microsoft Support – Share your calendar in Outlook (2025)
- Microsoft Support – Fix issues with sending, receiving, or delaying emails in Outlook (2025)
- Microsoft Support – Turn on or off Cached Exchange Mode (2024)