Some iCloud data isn't syncing? How to force and fix it on Mac

Confused by the message, 'some iCloud data isn't syncing' on your Mac? Yes, I've seen it too, and in my experience, it usually comes down to a couple of things:

• Servers are down

• Account verification

• Unstable network connection

• Time & date mismatch

• Misconfigured app settings

• Stalled sync daemons

• iCloud storage full

• Outdated software

• System glitch

I've chased this issue across my MacBook Pro and found reliable ways to force sync and repair the connection. Below are six fixes you can try today.

6 ways to fix the message that some iCloud data isn't syncing on MacBook

Before we dive into fixes, check if the network connection is stable. You can use speedtest. On an iPhone, make sure that Low Data Mode is disabled in Wi-Fi and Cellular preferences in Settings. Also, in Cellular Settings, enable iCloud backup.

Once you've checked the basics, proceed with the tips below. 

1. Check if iCloud servers are down 

First off, you need to rule out that iCloud services are not down. If they are, all you can do is wait until the issue is fixed since you cannot deal with it on your own.

Here's how to check:

1. In a browser of your choice, go to System Status. 
   
2. Find iCloud services. 
3. If the symbols next to it is yellow or red, wait for Apple to fix it. If you see green dots, follow the tips below one by one.

2. Verify basic settings on Mac and other devices

If there are no issues with Apple servers or outages, make sure your Mac is properly set up to sync the right apps. Here's how:

1. Open System Settings > Apple Account.

2. Sounds obvious, but first, check you're using your correct Apple ID (look for an email under your name).
   If you use iCloud on several devices, make sure that all of them are logged into the same Apple Account. On iPhone/iPad, you can check it in Settings > Apple Account. 
   

3. Now, go to iCloud and click See All next to Saved to iCloud.

4. All the apps you're having problems with need to be toggled on.

5. Take a few moments to check and toggle on apps that need to be. Repeat this step for other devices used for iCloud syncing.

While in settings, here are two more sections to check: 

📌 General > Software Update to install any updates available and rule out the possibility that this is outdated software that is causing the issue

📌 General > Date & Time to ensure there's no time and date mismatch (enable Set time and date automatically and choose Apple as source)

The steps are the same for Macs and iPhones/iPads.

3. Troubleshoot specific apps

If it's just a couple of apps that aren't syncing, like Contacts, Notes, or Photos, it's often a local app glitch, not a system-wide issue. You can force those apps to reconnect with iCloud. Let me break it down.

For Contacts:

1. Open up your Contacts app.

2. In the sidebar, look for All iCloud. If it's missing:
   
   Go to System Settings > Apple Account > iCloud > Show All > Contacts and make sure it's toggled on.

3. Toggle Contacts off, wait a few seconds, and turn it back on to refresh the connection.

4. Relaunch the Contacts app and wait a moment for it to update.

For Notes:

1. Open the Notes app, select from the top menu bar Notes > Accounts.

2. Select your iCloud account > See All.

3. Disable Notes under your account, then turn it back on.

4. This forces a sync reset; your notes should reappear after a few seconds.

For Photos:

1. Open System Settings and click your Apple Account (top of the sidebar).

2. Select iCloud > Photos.

3. Make sure iCloud Photos is toggled on.

4. To force a refresh:
   
   Toggle iCloud Photos off, wait about 10–15 seconds, then toggle it back on.

Tip: If you've run out of iCloud space, it may cause issues with syncing, especially if you use iCloud to sync photos. To upgrade your plan, go to System Settings > Apple Account > iCloud and click Manage next to a colored graph. From here, you can also downgrade a plan if needed. In most instances, 50 GB should be enough if iCloud Photos is disabled. If it is enabled, consider upgrading to 200 GB or 2 TB. If you do not want to upgrade, try freeing up some space first — check out this guide for the most effective tips on how to do it.

4. Force a refresh for specific apps

You can force iCloud's underlying sync service to restart:

1. Open Activity Monitor from Finder > Applications > Utilities.

2. Search for bird (the iCloud sync daemon).

3. Select it, then hit the × button and confirm Force Quit.

4. The system will restart bird automatically, which often triggers sync to resume.

This kill and restart is a lightweight way to clear stuck sync queues.

5. Restart your Mac 

Sometimes everything just gets tangled. A clean restart helps reset internal states:

1. Save your work, then choose Restart from the main Apple menu.

2. After reboot, give iCloud a few minutes to reconnect and resume sync.

I've had cases where a full restart made lagging apps catch up instantly.

6. Sign out and back into iCloud

If all the other fixes fail, it's time to re-establish the connection:

1. Go to System Settings > Apple Account.

2. Click Sign Out (you'll be asked whether to keep a local copy, say yes).

3. Restart your Mac.

4. Sign back in with your Apple ID and re-enable all iCloud services.

This often resets internal sync tokens and resolves verification that may have broken quietly.

Special cases: Some iCloud data isn't syncing Mac

When you use a new Mac or when you've just installed a new major macOS update, you may see the some iCloud data isn't syncing prompt because Apple requires device/proof verification (especially for end-to-end encrypted data like passwords or messages). In those cases:

1. Go to System Settings > Apple Account, look for a message under your name, and click the Resume Data Sync button.

2. You may be asked to enter a passcode from a previous device to reauthorize syncing of sensitive data.

3. After you authorize, the syncing backlog often clears automatically.

Keeping iCloud sync reliable on Mac

When some iCloud data isn't syncing, don't let it slide. I start by checking toggles, reconfiguring the affected app, and then force-restarting the bird daemon. If that still fails, restarting or signing out/in often restores full sync.

To keep things clean going forward, I also use two features from CleanMyMac. First, Cloud Cleanup (to clean up local synced cloud files and manage my iCloud data, and then My Clutter (to remove old, unused files to keep performance optimized). Here's how they work:

1. Get your free CleanMyMac trial — you can test all tools for 7 days free.

2. First, select Cloud Cleanup > Scan.

3. Review results and manage your iCloud.
    
   

4. Next, click My Clutter > Scan.
   
5. Click Review All Files, select what you no longer need, and remove the clutter.

Do those cleanup steps before forcing sync; it reduces friction, speeds up the recovery, and makes sure your Mac isn't blocked by leftover junk.

Frequently asked questions

What is iCloud sync and how does it work?

iCloud sync is a cloud-based service that automatically updates data across all devices logged into the same Apple Account (formerly Apple ID). It handles files, photos, contacts, calendars, notes, passwords, and app data. 

iCloud sync vs Google Drive sync — which is more reliable?

It all depends on what you're looking for. If you want a "set-and-forget" seamless synchronization within the Apple ecosystem, iCloud Drive sync is more reliable and seamless. However, if you need more flexibility and want to sync data among Apple and non-Apple devices, Google Drive may be a better option.

How much free storage does iCloud give by default?

By default, every Apple user gets 5 GB of iCloud storage for free, but you can upgrade in iCloud settings at any moment. Note that iCloud sync is on by default, so these 5 GB fill up too quickly.