My data is only partially syncing

Usually means a sync was interrupted before completing. Trigger a manual sync (pull-to-refresh on iOS / Android, or ⌘S on Mac) and let it run all the way through. If the issue persists across multiple manual syncs:

1. On the device with the most up-to-date data, create a backup.
2. On that same device, open Settings > Sync > Next sync action on iPhone or iPad, 2Do > Settings > Sync > Next sync action on Mac, or Settings > Sync > Next Sync Action on Android.
3. Choose Replace Server Data, then trigger a manual sync and let it finish.
4. On each device that is missing data, choose Replace Local Data from the same picker.
5. Trigger a manual sync on each out-of-sync device. This pulls the clean server copy down to that device.

Syncing with Todoist or Apple Reminders?

Those methods don't offer Replace Server Data. In step 3, run Merge Sync from the device with the correct data instead, then keep step 4's Replace Local Data on the others.

Learn more in Replace server data or Replace local data?, Sync Overview for Mac, Sync Overview for iOS, or Sync Overview for Android.