Ventura 13.7 iMac not syncing with iPhone 18.3.2

Sync your iPhone, iPad, or iPod using your computer

Learn how to sync music, movies, and more using your Mac or PC.

Before syncing your content, consider using iCloud, Apple Music, or similar services to keep content from your Mac or PC in the cloud. This way, you can access your music, photos, and more on your iOS or iPadOS devices when you aren't near your computer.

Depending on the macOS version your Mac has, you might need to use Finder or iTunes to sync your iPhone, iPad, or iPod touch using your computer. If you have a PC, you will need to use iTunes or the Apple Devices app to sync with your iPhone, iPad, or iPod touch.

Use the Finder to sync your iPhone, iPad, or iPod touch with your Mac

Sync over Wi-Fi instead of USB

When your device is connected to your Mac via USB, you can set up your Mac so that in the future it syncs over Wi-Fi instead.

1. Select your device in the sidebar of the Finder window, then click General on the right. 
2. Scroll down and select “Show this [device] when on Wi-Fi.” 
3. Click Apply.

You can now unplug your device from your Mac. When your Mac and device are on the same Wi-Fi network, your device appears in the Finder sidebar, and it syncs automatically over Wi-Fi whenever it's plugged in to power.

Hello tony.vidmar,

First, try to reboot your Mac. If the issue persists, disconnect your Apple Account (Apple ID) from your Mac, reboot the Mac and reconnect your account.

A couple of things

OP wrote " why suddenly Ventura 13.7 iMac not syncing Notes nor Messages with iPhone 18.3.2 "

Current Ventura is Ventura 13.7.4

Make sure Notes and Messages are Turned ON in System Setting / Preferences >> User Name >> iCloud >> Save to iCloud

If they are already On - Turn them Off

Pause and reverse the above

This may Force a Re-Sync

If the does not work

Suggest following the advise from @ 6x6 👍 and sign Out of iCloud completely

Restart the computer and Sign Back into iCloud account

Apple Support per se is not here

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