iCloud Mail not syncing across devices

I had this exact problem on the new iPhone 12 Mini.

I was receiving email across all devices, but any changes made on the phone wouldn't reflect on the other devices, inc. laptop and iPad. (Changes made on other devices synced just fine - even on the iPhone.)

I tried EVERYTHING: signing in and out of iCloud (on all devices), deleting and reinstalling accounts, etc.

The solution was to DELETE THE MAIL APP ON MY IPHONE. I reinstalled it and suddenly everything worked fine, syncing between all devices. Hope this helps.

Hi,

I solved my issue after 2 simple steps :

1/ de-actived and re-actived email sync in iCloud settings => did not fix the problem

2/ de-connected and re-connected iCloud account on iPhone => fixed the problem :-)

Only painful point was that I had to re-activate all my payment cards in Apple Pay.

Hope this helps

Thanks! That worked and seems to be the easiest solution.

1. I just deleted the Mail app.
2. Then re-downloaded the Mail app from the app store.
3. And then went to settings -> Apple ID -> iCloud to turn Mail on again.

(If you don't do the last part and try to open the Mail app, you'll be asked to sign in and when you do it'll tell you that that account already exists).

Have you tried to Rebuild the Mailbox - Mailbox>Rebuild ? Worked for me:)

Go to the App Store and download the mail app again. If you have, go to iCloud settings and turn mail back on them kill the mail app and reopen it.

Hello JD135,

Thank you for posting in the Apple Support Communities. I understand that iCloud Mail isn't syncing between your Mac and iPhone, and signing out, then in to your iCloud account on all devices hasn't resolved the issue. I'd like to assist you today.

For this issue, I suggest ensuring that you have enough available iCloud storage. Here's how to check:

Manage your iCloud storage

From there, I recommend ensuring that your devices are fully updated per the, "First things first" section here:

Get help using iCloud Mail

If this concern isn't resolved, contact Apple Support for further assistance: 

Get Support

I hope this information is useful. Kind regards.

What are you mail settings ? do you use vpn services see https://support.apple.com/en-us/HT204051

What is the version of iPhone do you update the iPhone https://support.apple.com/guide/iphone/update-ios-iph3e504502/ios

https://support.apple.com/en-us/HT204204

It's documented that people were no longer able to search their mail following a Big Sur upgrade. The solution was to rebuild the mailboxes and re-index Spotlight.

Perhaps trying to rebuild the mailboxes that fail synchronization might shed light on the issue since Mail.app needs to communicate with Mail server to re-build... thinking somewhat like synchronization. Here's something on the topic https://discussions.apple.com/thread/252495099

Hope proves helpful.

Mail should be synced between ALL Apple devices not just between iPhone and Mac or iPad and Mac. I don’t own a Mac. I own an iPhone and iPad. This was never a problem before mid 2019. I used watch the notifications disappear from my iPad as I read mail on my iPhone. I should NOT have to go to each one and open the Mail app to clear them. There’s something wrong with iCloud services themselves because the same happens with reminders as well.

For no explicable reason my 3 devices using Apple mail are suddenly not syncing mail. Read/delete not corresponding between devices. All software updates, iCloud storage checked, iCloud setting checked, mail deleted then reinstalled on all devices. Have followed all Apple advice still not working 🤔🤔

I am so glad to know that this is a problem for someone else. However, mine is a little different.

If I read a message on my iPhone, it gets marked read on iCloud.com but not my iPad. If I read it on my iPad, it will get marked as read on iCloud.com but not on my iPhone. If I read it on iCloud.com it will not get marked as read on my iPhone OR my iPad. This is an issue I have had since mid 2019 and iOS 12. I used an iPhone 7 Plus with an iPad 2nd gen. I have used am iPhone 7 Plus with an iPad 6th Gen. I am now using an iPhone 11 Pro with an iPad 6th Gen.

No matter the combination of devices, the only time the Mail app will update is when I open it on BOTH devices which defeats the purpose. So frustrating.

I have been in touch with Support and a Senior Support Rep who was supposedly working with the engineers. Somehow, that communication has fizzled out and the last 2 messages I sent to him have gone unanswered. I have a case number and everything.

Mails are only synced ( mirrored ) between iPhone / Mac when same Apple ID and password are signed in on the same network the Apple ID say should be example1@icloud.com

When ever a mail is deleted from a single device it will be deleted from its hardware address and not deleted from another device it could be Mac / iPhone and moved to bin folder of the web account / and simultaneously in IMAP accounts .

See these https://support.apple.com/en-us/HT208661

https://support.apple.com/en-in/guide/mail/mlhlp1001/mac

We are members in this community and as per terms of use can't discuss on their policies the respectful way is to send feedback https://www.apple.com/feedback/icloud.html

https://www.apple.com/feedback/mail.html

✅ CONTINUED BEST PRACTICE (for me):

As long as I keep my Mac running 24 hours a day, Mail seems to sync properly. That means no standby mode, disabling any energy saver settings and no sleep. Turn the [docking station] monitor off (or reduce brightness) when not using. Currently using wi-fi but I plan to connect directly to a router in the new office.

Currently, I’m using a MBP on 10.15.6. I have two iPhone models on slightly different iOS receiving and syncing mail properly.

What the Mac has to do with Mail syncing, I have no idea. If I disconnect the MBP from power and it goes into standby mode, I'll start seeing a slowdown and messages not working well together.