iCloud Sync not working with iPhone, works fine for Mac.

App & System Services iCloud CloudKit

Created Mar ’26

Replies 37

Boosts 17

Views 9.3k

Participants 24

I've been working on an app. It uses iCloud syncing. 48 hours ago everything was working 100%. Make a change on the iPhone it immediately changed on the Mac. Change on the Mac, it immediately changed on the iPhone. I didn't work on it yesterday. I updated to iOS26.4 on the iPhone and 26.4 on the Mac yesterday instead.

Today, I pull up the project again. I made NO changes to the code or settings.

Make a change on the iPhone it immediately updates on the Mac. Make a change on the Mac, nothing happens on the iPhone. I've waited an hour, and the change never happens. If you leave the iPhone app, then return, it updates as it should.

It appears that iCloud's silent notification is to being received by the iPhone. Anyone else having the issue? Is there something new with iOS 26.4 that needs to be adjusted to get this to work? Again, works flawlessly with the Mac, just not with the iPhone.

Impy OP

Mar ’26

This seems to also be preventing syncing of Passwords.app inc shared passwords.

bdkjones OP

Apr ’26

Same exact issue. Filed FB22390203.

I hope there's some accountability for the engineers who shipped such a MASSIVE regression. They definitely ought to be reassigned to a less-critical, simpler project.

bdkjones OP

Apr ’26

Since this is obviously a widespread issue and affects Apple's own apps, it might be useful to draw some public attention to it. Submitting a tip to the usual Apple news sites (the forums hilariously edit the names out!) seems like a good start.

I know Apple likes to say, "Running to the press never helps," but....it absolutely does. The more high-profile the issue becomes, the more likely Apple is to push a 26.4.1 release to fix it.

The alternative is waiting 1-2 months for the 26.5 release.

lionelng OP

Apr ’26

Tested my app which uses CloudKit automatic configuration. The data will sync correctly on iOS 26.5 beta 1 now. Hope Apple will push an update for 26.4.1 soon.

DTS Engineer OP

Apple

Apr ’26

Now that iOS 26.4.1 was out, could folks please give it a try and share if the issue is fixed? Thanks.

Best,
——
Ziqiao Chen
 Worldwide Developer Relations.

bdkjones OP

Apr ’26

The issue is resolved in iOS 26.4.1.

Let's hope they added some tests so it never happens again.

lionelng OP

Apr ’26

I have tested my apps, the sync issues have been fixed in iOS 26.4.1. Cross syncing between 26.4.1 and 26.5 beta works fine too.

Jeko OP

Apr ’26

Yes, fixed in 26.4.1 😅

Eboles OP

Apr ’26

Even with the 26.4.1 fix from iOS, I'm still having iCloud sync issues between iOS and WatchOS 26.4. Anyone else seeing the same thing? WatchOS hasn't had an update.

dnlfrst OP

Apr ’26

I am still experiencing the same issue as before on both iOS 26.4.1 and macOS 26.4.1!

Felix_Hauser OP

Apr ’26

Filed as well: FB22468964

Very sad that this is my first forum contribution.

jbjones27 OP

I have had this exact issue off and on over the past few months. I am using Codex to help code my app and finally after some extensive debugging and setting up a simple test App specifically to test CloudKit syncs, Codex came up with a fix for me. In summary: Fixed CloudKit sync wakeups by replacing the shared SyncSignal subscription with per-device subscriptions. After this simple change, all the data sync between my MacBook Air, iPhone, and iPad has been rock-solid. Hope this helps someone.