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Why doesn't BusyCal sync immediately or frequently in the background on iOS?

BusyCal syncs immediately when you launch the app and frequently while actively using it. However, background sync is controlled entirely by iOS. Apple's iOS decides when (and if) to allow background syncing based on multiple factors.

How iOS Background Sync Works​

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iOS uses intelligent scheduling for background app refresh based on:

  • Usage patterns - Apps used frequently get priority
  • Battery level - Low battery restricts background activity
  • Network conditions - Poor connectivity delays syncing
  • Device resources - Available memory and processing power
  • Time of day - iOS learns when you typically use apps
iOS Controls Background Sync

There's no way for any app to force specific sync intervals. The more you use BusyCal, the more iOS prioritizes keeping it updated in the background—but there are no guarantees.

Common Issues Preventing Background Sync​

While iOS manages background sync automatically, certain user actions can completely prevent it from working. Here are the most common issues that block background syncing:

1. Background App Refresh Disabled​

Check this first:

  1. Open Settings > General > Background App Refresh
  2. Ensure Background App Refresh is ON at the top
  3. Ensure BusyCal is specifically enabled in the list

2. Force-Quitting Apps​

This is the #1 cause of sync issues:

Never Force-Quit BusyCal

When you force-quit apps (swipe up and flick apps away), iOS interprets this as "I don't want this app running" and completely disables background sync for that app. This prevents:

  • Background syncing
  • Badge count updates
  • Widget updates
  • watchOS updates
  • Notification delivery in some cases

Apple advises against force-quitting apps as it actually uses more battery and breaks background functionality.

If you've force-quit BusyCal:

  • You must manually launch the app again
  • iOS will then reconsider it for future background refreshes
  • It may take time for iOS to "trust" the app again

3. Frequent Device Restarts​

After restarting your iPhone:

  • iOS doesn't automatically launch any apps
  • You must manually open BusyCal once
  • Only then will it be eligible for background refresh

Avoid unnecessary restarts - modern iPhones are designed to run continuously.

Best Practices for Reliable Sync​

  1. Leave BusyCal running - Don't force-quit the app
  2. Use the app regularly - iOS prioritizes frequently-used apps
  3. Keep Background App Refresh enabled - Check settings periodically
  4. Avoid unnecessary restarts - Only restart when truly needed
  5. Maintain good battery levels - Low battery restricts background activity

Background sync limitations are an iOS design decision to balance functionality with battery life. By following the best practices above, you'll get the most frequent background updates iOS allows—but immediate sync is only guaranteed when you open the app.

Manual Refresh

If you need immediate updates, simply open BusyCal. The app will sync instantly upon launch, ensuring you have the latest calendar data.

"But other calendar apps sync immediately in the background!"​

Some apps appear to sync instantly because they use push notifications from their own servers. This requires the app company to run and maintain their own cloud servers and store some information about your calendar(s) there.

BusyCal takes a different approach: you own and control your data. It syncs directly with your chosen calendar services (iCloud, Google, Exchange, etc.) without routing through our servers. This gives you complete privacy and control, but means we must follow iOS's standard background sync rules.

BusyCal does however support Push Sync for services that allow 3rd parties to connect via their public APIs, specifically:

  • Google Calendar - Push notifications for instant updates
  • Microsoft Outlook/Office 365 - Real-time sync via Microsoft Graph API

When using these services with Push Sync enabled, iOS will automatically launch BusyCal in the background to prompt it to perform a background refresh.

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