Why Your External Calendars Aren’t Showing on the Planner

If a Google, Apple, or other external calendar isn't appearing inside Helium, the issue is usually related to the External Calendar settings, an invalid URL, or the feed being automatically disabled after an error.

1. Check Your Filters

The Planner has filter options that control what's displayed. If Remember filter selections is enabled (found in Settings → Preferences), filters from a previous session may still be active.

• A highlighted filter indicator means filters are currently active
• Verify that External Calendars is selected in the filters

2. Wrong View

The Todos view displays only Assignments—External Calendars will not appear there. Switch to Week, Day, Month, or Agenda view.

3. The External Calendar Is Not Shown on the Planner

Each external calendar has a Show on calendar toggle. If it's turned off, the calendar won't appear in the Planner.

Important: If Helium encounters an error while loading an External Calendar (for example, an invalid or unreachable URL), it will automatically disable the calendar.

How to Check

1. Open Settings → External Calendars
2. Find your calendar in the list
3. Make sure the Show on calendar toggle is turned on

If the toggle keeps turning itself off, the URL may be invalid—see the steps below.

4. The iCal/ICS URL Is Incorrect or Invalid

The URL for an External Calendar must return a valid iCal/ICS feed. HTML links to a webpage or a Google Calendar "share" URL will not work.

Check the following:

• The link ends with .ics (not required, but a common sign of a valid feed)
• The link was copied from your calendar app's "Subscribe" or "Add by URL" option (see How to Sync Google, Apple, or Other Calendars in to Helium Using External Calendars)
• There are no extra spaces before or after the URL

If the URL is invalid, Helium will disable the feed automatically the next time it tries to load it.

5. Your Calendar App's iCal/ICS URL Changed

Some services rotate or invalidate feed URLs after account changes (e.g., changing your password, switching accounts, or adjusting privacy settings). If the feed suddenly stopped working:

• Re-copy the URL from Google or Apple Calendar (see How to Sync Google, Apple, or Other Calendars in to Helium Using External Calendars)
• Update it in Settings → External Calendars

6. The External Calendar Is Refreshing Slowly

Helium refreshes External Calendars on a periodic basis. If the source calendar updates slowly or the calendar provider caches the feed, changes may take time to appear. This is normal.

Helium Classic

The same troubleshooting steps apply in Helium Classic. The key navigation differences are:

• Filter settings are at Account → Settings → Preferences
• External Calendars are also managed within Account → Settings → Preferences, under the External Calendars section
• The toggle to show/hide an external calendar is the Enabled checkbox (rather than the "Show on calendar" toggle in the new Helium)

Helium Classic will remain available through at least Summer 2026.