Hi there! Thanks for reaching out about your Proton Calendar issue. Just to make sure I understand correctly: you have multiple calendars besides your primary one, and you've selected them to show in the Proton Calendar app on your Mac running OS X 10.15, but only the primary calendar is actually visible. Is that right?

Also, are these other calendars Proton calendars (like additional calendars within the same Proton account), or are they external calendars (like Google or Outlook) that you've added to Proton Calendar? Knowing this will help me provide the most relevant steps.

In the meantime, here’s a general approach to troubleshoot this:

1. Check Calendar Status in Settings:
Open Proton Calendar in the web app at proton.me on your Mac browser (this sometimes gives more detailed control than the app). Go to Settings → Calendars. Look for the section "Other calendars" or similar, and ensure that those calendars are listed there and marked as active or enabled, not "Disabled" or "Not synced."

2. Verify Sync Status:
Sometimes external or secondary calendars may show as “Not synced.” If that’s the case, disconnect and reconnect the calendar or refresh the sync.

3. Restart the Proton Calendar app:
Quit the Proton Calendar app completely on your Mac and restart it. Sometimes the app needs a restart to refresh calendar visibility.

4. App Version and Updates:
Ensure your Proton Calendar app is updated to the latest version available on your Mac. Outdated versions may have sync or display bugs.

5. Sign Out and Back In:
Sign out of Proton Calendar and sign back in. This can reset calendar syncing and permissions.

6. Check Filters or Views:
Within the app, verify if any filters or specific view modes are hiding secondary calendars by accident.

If these steps don't help, could you please let me know:

- Whether these missing calendars are shared calendars, additional personal calendars, or external calendars added to Proton?
- Whether you experience this issue both in the Mac app and the web app at calendar.proton.me?

This info helps me pinpoint the solution better! Looking forward to your reply.

the missing calendars are additional personal proton calendars, they are shared. on the mac it's ok, it's just on the app

Thanks for clarifying that these missing calendars are additional personal Proton calendars you have shared with others, and that the issue only happens in the Proton Calendar app on your Mac (not in the web app). That’s a helpful detail!

This seems to be a known limitation specifically with the Proton Calendar app on macOS or mobile apps, where shared calendars sometimes don’t show up properly even if you have them selected to display. The Mac app might not fully support viewing or managing shared calendars yet, although these show fine via the web app.

Here’s what I suggest to try next:

1. Double-check sharing permissions:
Even if the shared calendars appear in the web app, verify you still have the correct access permissions—“Editor” rights or at least “Viewer” rights. Owners could remove or change sharing settings, affecting visibility on apps.

2. Force a sync refresh:
- In the Proton Calendar app on your Mac, try signing out and signing back into your account to force the app to refresh its sync of your calendars.
- Quit the app entirely (Cmd + Q), then restart it and see if shared calendars appear.

3. Check if the app offers a “Refresh” option:
Some versions of the app include a manual “Refresh” or “Sync” option in app menus or settings. Use that if available.

4. Use the web app as a workaround:
Until shared calendars have full support in the Mac Proton app, accessing calendar.proton.me on your browser remains the best way to view and manage all shared calendars reliably.

If this behavior continues and you want to confirm if it’s an app limitation or bug, you could file feedback directly to Proton here:
https://proton.me/support/calendar
This helps the team prioritize shared calendar support improvements for desktop and mobile apps.

Please let me know if signing out and back in or refreshing brings back your shared calendars in the app, or if you’d like me to help walk you through those steps!

Are you satisfied with this solution so far?

Troubleshooting Proton Calendar sync issues on mobile

Thanks for your question about troubleshooting Proton Calendar sync issues on mobile. Since your device is a Mac running OS X 10.15, I assume you might want similar tips applicable to mobile devices or just general syncing advice that can sometimes help across platforms. Here are some common Proton Calendar mobile sync troubleshooting steps that might be helpful:

1. Pull-to-Refresh: Open the Proton Calendar app on your mobile device and try pulling down the calendar view to refresh the sync manually. This often triggers the app to update events added elsewhere, like the web app.

2. Check Calendar Visibility: Ensure all your calendars are toggled to be visible in the app settings, so the app knows to sync those calendars.

3. Sign Out and Sign Back In: Signing out of the Proton Calendar app and then back in can help reset the sync connection.

4. Reinstall the App: If issues persist, uninstall and reinstall the app to clear potential app cache or corrupted data.

5. Edit Events via Web: Sometimes editing or adding events on the Proton Calendar web app can prompt the mobile app to re-sync and catch up on missing events.

6. Check Internet Connection: Make sure your mobile device has a stable internet connection. Sync needs an active connection to update events.

Since your original issue concerns the Mac app, some of these steps also apply there—like signing out/in, restarting the app, or reinstalling it. Note that Proton Calendar sync issues and limited shared calendar support on Mac apps are known and Proton actively improves these areas.

For persistent or complex sync problems, you can always reach out to Proton support directly at https://proton.me/support/calendar or report bugs with detailed info about your device and app version.

Does this help address your question about mobile app sync? Would you like me to guide you step-by-step through any of these sync troubleshooting actions?