When sync gets stuck on a Mac, it usually looks the same in every app: endless “Syncing…”, old data on one device, or changes that never arrive.
This guide walks through the fixes that solve most “sync won’t update” problems on macOS, without assuming the app is the problem.
Before you start: pick one “test change” (like creating a note, renaming a file, or toggling a setting) so you can quickly see when sync starts working again.
1. Confirm it’s not a server outage (fast reality check)
Many sync issues are upstream: the app’s service is degraded, or your account region is having trouble.
- If the app has a status page, check it first.
- If it’s an Apple service (iCloud, Notes, Reminders, Photos), check Apple System Status.
- Try the same account on another device or the web (if available). If it’s broken everywhere, local Mac fixes won’t help much.
If there’s an outage, avoid signing out/in repeatedly—wait it out and try again later.
2. Reset your network path (Wi‑Fi, VPN, DNS)
Sync is sensitive to “almost connected” networks—where browsing works, but long-lived connections fail.
- Toggle Wi‑Fi off/on, or switch to a phone hotspot for 2 minutes to test.
- If you use a VPN, disconnect it temporarily and retry sync.
- Restart your router if multiple devices are slow to sync.
- If you recently changed DNS/ad blockers, revert to automatic DNS briefly.
Quick test: if sync works on a hotspot but not on your Wi‑Fi, the issue is your network path (router/VPN/DNS/filter), not the app.
3. Check date/time and certificate trust issues
If your Mac’s time is off, secure connections can fail silently and sync may spin forever.
- Open System Settings → General → Date & Time.
- Turn on automatic time and automatic time zone (or re-enable them).
Then fully quit and reopen the affected app and retry your “test change.”
4. Make sure the app is allowed to sync in the background
macOS can restrict background activity, and some apps look “open” but aren’t allowed to refresh when idle.
- System Settings → General → Login Items: look for the app under “Allow in the Background” and enable it if it makes sense.
- System Settings → Battery: if you use Low Power Mode, try turning it off briefly while you sync.
- If you use Focus modes or network filters, make sure they’re not limiting the app.
Single-sentence check: if sync only works while the app stays in front, this is the likely cause.
5. Clear the “stuck queue”: restart the app, then restart the Mac
Sync engines can get wedged—especially after sleep, network changes, or OS updates.
- Quit the app completely (not just closing the window). Reopen and wait 2–3 minutes.
- If it’s still stuck, restart your Mac. This resets background agents that many apps rely on.
If you’re troubleshooting iCloud-related sync: restarting can re-kick iCloud background services without requiring you to sign out.
6. Check storage and keychain/account authentication
Two common “hidden” blockers: the Mac is low on disk space, or your account token is expired and needs re-auth.
- Storage: keep at least 5–10 GB free. If you’re near zero, sync databases can’t update reliably.
- Account auth: open the app’s account/settings area and look for any “Sign in again”, “Re-enter password”, or “Fix account” prompts.
- If it’s an Apple-account sync issue, check System Settings → Apple Account for any security prompts.
If you do choose to sign out/in, do it once—and only after confirming you won’t lose unsynced local changes.
Final thoughts
Most Mac sync problems come down to network path (VPN/DNS), background restrictions, or a stuck sync queue after sleep.
Work in order, keep one test change, and you’ll usually identify the exact step where sync starts moving again.