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Sync with iCloud CalDAV

iCloud sync in 2Do works over CalDAV. This lets 2Do read and write tasks through iCloud using your Apple ID and an app-specific password.

Reminders is separate

Apple's Reminders app does not sync over CalDAV: tasks synced through 2Do's iCloud option will not appear in the Reminders app, and changes made in Reminders do not reach 2Do. If you want your tasks inside Reminders, use the Apple Reminders sync method instead. iCloud CalDAV is mainly worth choosing when you also use non-Apple devices (Android, Windows) or other CalDAV task apps on the same account.

What iCloud Sync Carries​

  • Core task fields — title, notes, dates, recurrence, priority, action, location, sub-tasks.
  • Multiple alarms per task sync through iCloud CalDAV as-is.
  • A maximum of one picture and one audio recording per task can sync when attachment sync is enabled.

What Stays on This Mac​

Some 2Do-only features stay on this Mac and are not carried by iCloud CalDAV sync:

  • Smart Lists
  • Tag groups
  • List groups
  • Unused tags
note

Other apps and devices signed in to this account see your projects and checklists as a flat list of tasks.

For the fullest sync of your 2Do setup, including Smart Lists, tag groups, and list groups, Dropbox or WebDAV carry more.

App-Specific Password Requirement​

Apple requires two-factor authentication for any third-party app accessing iCloud. Your normal Apple ID password won't work: generate an app-specific password at appleid.apple.com → Sign-In and Security → App-Specific Passwords, and enter that in 2Do instead. App-specific passwords can be reused across apps and devices. Save yours somewhere secure, or generate a new one any time.

Best Practices​

A few things that catch people out:

  • Use your @icloud.com address, not @mac.com. If your Apple ID also has an @mac.com address, enter the @icloud.com address in 2Do.
  • Use your primary Apple ID, not an alias. iCloud aliases do not work for CalDAV sign-in — only the primary email address that owns the Apple ID.
  • Set your Mac's date and time to automatic. Under System Settings > General > Date & Time, turn on Set Automatically. If your Mac's clock is wrong, the app-specific password will silently fail without an obvious reason.
  • Resetting your main Apple ID password revokes all your app-specific passwords. You'll need to generate a new one and re-enter it in 2Do.

Setup​

  1. Make sure two-factor authentication is enabled on your Apple ID.
  2. Generate an app-specific password at appleid.apple.com → Sign-In and Security → App-Specific Passwords. Label it 2Do so you can revoke it later.
  3. Open 2Do > Settings > Sync.
  4. Choose iCloud CalDAV from the Account Type pop-up.
  5. Enter your Apple Account and the App-Specific Password you generated, then click Connect.
  6. 2Do connects, discovers your iCloud CalDAV task lists, and starts syncing.
  7. Repeat on each device with the same Apple ID. The first device populates iCloud; subsequent devices use Replace Local Data to pull down.
Your first sync

Close Settings and press ⌘S (or click the Sync toolbar button) to run the first sync. When both sides already hold data, 2Do asks how to combine them; see Merge vs Replace before choosing. You can re-run any of these later from Settings > Sync > Next sync action; it applies once, then returns to Sync Normally.

Daily Sync​

iCloud CalDAV syncs continuously while 2Do is running. Press ⌘S to force an immediate sync.

Troubleshooting​

"Password is incorrect" / can't log in / cryptic -1012 error​

Most often this is one of:

  1. You're using your normal Apple ID password instead of an app-specific password. Generate one at appleid.apple.com and use that.
  2. The app-specific password has been revoked because you reset your Apple ID password. Generate a new one.
  3. Your Mac's clock is wrong. Make sure System Settings > General > Date & Time > Set Automatically is on.
  4. You used an alias or @mac.com address. Use your primary @icloud.com address. If none of those help, the cleanest fix is to remove the iCloud account from 2Do and re-add it: 2Do > Settings > Sync → disconnect iCloud → re-add with a freshly-generated app-specific password.

"Forbidden" error during sync with iCloud​

This error usually means the credentials being sent aren't accepted at all, typically because of one of the points above (wrong password type, alias, expired). Generate a fresh app-specific password and re-enter.

Duplicate tasks after Reminders changes​

If your tasks suddenly appear twice, you may be syncing the same iCloud tasks through two paths. Remove one of the two sync sources from Settings > Sync to clear the duplicates.

Tasks disappear after changing lists in Reminders​

Apple Reminders is separate from iCloud CalDAV. Reminders stores its lists in Apple's private Reminders system, not on iCloud CalDAV, so a list that only exists inside Reminders cannot sync through iCloud CalDAV. If you want your tasks to live inside the Reminders app, use the dedicated Apple Reminders sync method instead.

Recovery: 2Do creates backups automatically every 24 to 48 hours. Open 2Do > Settings > Backups, restore from a recent backup (a backup's ⋯ menu > Restore…), and choose Replace Server Data during the next sync prompt to push your 2Do data back up to iCloud CalDAV. If you want to avoid Reminders-related changes entirely, use 2Do's own iCloud CalDAV lists or switch to Dropbox sync.

507 Insufficient Storage error​

Your iCloud account is out of storage. Free up space in iCloud, then retry sync.

301 Moved Permanently when syncing using CalDAV​

Apple occasionally moves CalDAV endpoints. Update 2Do to the latest version; newer builds follow Apple's redirects automatically.

A list I delete reappears after sync with Reminders​

This usually means another device still has that list and is pushing it back up. Delete the list on all devices, then sync.

Tasks I add to 2Do get deleted after some time​

This typically points at a stale sync state, usually two devices pulling against each other. See Tasks I add get deleted after some time and consider switching to Dropbox.

Adding another device​

Install 2Do, configure CalDAV against the exact same Apple ID (with a fresh app-specific password), and let the first sync pull your data down. See Setting up a new device.

One device showing different tasks​

Run a clean sync on the most up-to-date device, then choose Replace Local Data on the lagging ones. See One of my devices isn't syncing correctly.

Tips​

tip

If you rely on Siri to capture tasks into Reminders, remember that 2Do syncs with iCloud CalDAV lists, not with Apple Reminders.

tip

If you want all 2Do features and attachments to sync, use Dropbox sync.

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