What prerequisites are necessary for synchronization?

For synchronization to work reliably, certain requirements must be met. These vary depending on the synchronization type:

iCloud / CloudKit Synchronization

To synchronize your data via iCloud, you need:

  • Internet connection: Your device must be connected to the internet.
  • iCloud server availability: Apple servers must be accessible (you can check for occasional outages on the Apple System Status page).
  • Apple ID login: You must be signed in to iCloud with your Apple ID.
  • Sufficient iCloud storage space: Make sure your iCloud storage still has space for the synchronization data.

Folder Sync

If you use syncing via a folder (e.g., on a NAS or a network drive), please note:

  • Access to the folder: The folder must be accessible and mounted (e.g., connected to a network share).
  • Read and write permissions: You need both read and write permissions for the folder and all files it contains.
  • Stable connection: Network folders require a stable network connection (LAN or Wi-Fi).

Tip: Check whether you can open the folder outside of the app and save files to it. If this is not possible, syncing will not work.

Device-to-device sync

For direct syncing between two devices (e.g., iPhone ↔ Mac or iPhone ↔ iPad), the following conditions must be met:

  • Wi-Fi enabled: Both devices must have Wi-Fi enabled and be on the same Wi-Fi network.
  • Access to the local network allowed:
  • On iOS/iPadOS: Check in the System Preferences whether the app has access to the local network (see screenshot below).
  • On macOS: Check the local network permissions in the System Preferences
  • Privacy & Security > Local Network > Enable SimpleumSafe
  • Bluetooth enabled and allowed: Bluetooth must be enabled on both devices, and the app requires the appropriate permission.
  • On iOS/iPadOS: Check in the System Preferences whether Bluetooth permissions are enabled (see screenshot below).
  • On macOS: Check in the System Preferences whether Bluetooth permissions are enabled
  • Privacy & Security > Bluetooth > Enable SimpleumSafe
  • Both devices unlocked: To enable the devices to find each other, they should be enabled and unlocked.

Note: In some Wi-Fi networks (e.g., corporate or guest Wi-Fi networks), connections between devices are blocked. In this case, synchronization may not work.

This is what the app settings should look like on iOS