Missing conversations on a Mac can mean Messages in iCloud is off, the devices use different Apple Accounts, or the first history download is unfinished. Open Messages > Settings > iMessage, check the account and enable Messages in iCloud.
Use Sync Now there to request an update. A Mac that cannot sign in and a Mac missing only carrier texts need separate checks from one that receives new iMessages but lacks older history.
Match the account before changing the sync switch
On the Mac, open Messages > Settings > iMessage and read the Apple Account shown. On the iPhone, check Settings > Apps > Messages > Send & Receive. Compare the account used by Messages on both devices.
Apple documents this account requirement in its Messages in iCloud setup guide. An account used for another Apple service does not establish which account Messages is using.
Also compare System Settings > your name on the Mac with Settings > your name on the iPhone. The intended account must be used for iCloud as well as Messages; matching an App Store purchase account alone is insufficient.
Status: Apple's Mac message-history sync and iPhone forwarding guidance checked October 29, 2026. Initial syncing has no fixed completion time here. No account was accessed or reconfigured.
If the accounts differ, correct the Messages sign-in for the device using the unintended account. Keep track of which account owns the history before signing out; do not create a new account to repair a missing library.
If the Mac instead refuses the password or reports an unknown error, use the Mac iMessage sign-in fixes first. Sync controls cannot retrieve history while the intended account remains inaccessible.
Enable the shared history on each device
On the Mac's iMessage settings tab, select Enable Messages in iCloud. This connects Messages to its shared history rather than relying only on messages newly delivered to the Mac.
On the iPhone, open Settings > your name > iCloud. Tap See All or Show All, choose Messages in iCloud, then turn on Use on this iPhone.
Apple's guide gives that iPhone label for iOS 17.2 and later. On iOS 16 through 17.1, its route uses Show All > Messages > Sync this iPhone instead.
Messages in iCloud also requires two-factor authentication and iCloud Keychain. Check those requirements if the feature cannot be enabled, along with available software updates for each device.
Enabling the feature creates a shared message library. Deletions can propagate to the participating devices too; do not delete conversations on one device as a way to force the other to download them.
Request an update and let the first download finish
Return to Messages > Settings > iMessage on the Mac and click Sync Now. Apple says this requests the most recent messages, including when setting up a new Mac. Normal syncing continues automatically afterward.
Keep an internet connection available and inspect the history again after syncing has had time to progress. Apple does not supply a universal completion time for an entire message library.
The setup guide explicitly allows new messages to be sent and received while the initial history is still arriving. A fresh message appearing therefore does not prove that every older attachment has finished downloading.
Our comparison is to check one known older conversation and one new message after the request. Record which is missing if the difference persists. That is more precise than treating every absent item as the same sync failure.
Check receiving addresses when only some chats are absent
In the Mac's iMessage settings, inspect You can be reached for messages at. Select the phone number and email addresses that should receive messages on this Mac.
Compare them with Send & Receive on the iPhone. A conversation sent to one address can behave differently from another sent to the phone number if the receiving selections differ.
The Start new conversations from choice controls the address or number used for newly started chats. Changing that choice is not a command to download historical messages.
Separate missing carrier texts from missing iMessage history
SMS, MMS and RCS on a Mac rely on a powered-on iPhone with a working network and working text messaging. Apple's text-forwarding guidance explains that requirement.
Its current instructions say Text Message Forwarding is built into Messages in iCloud. A device already using that feature does not need a second independent forwarding setup.
Without Messages in iCloud, the iPhone has Settings > Apps > Messages > Text Message Forwarding for permitted devices. The Mac carrier-text checks cover that route and incorrect delivery labels.
For history still missing after the account, switches and receiving addresses are correct, contact Apple Support.
Include both software versions, whether Sync Now progresses and whether old history, new iMessages or carrier texts are affected.
The Short Version
Match the Messages account, enable Messages in iCloud on both devices and request Sync Now on the Mac. Allow the initial history to arrive. Check receiving addresses for selective gaps and the iPhone forwarding route for carrier texts.
Isaac Smith is the founder and editor of PC Glance, a website that covers computers, laptops, and technology. He is a tech enthusiast and a computer geek who loves to share his insights and help his readers make smart choices when buying tech gadgets or laptops. He is always curious and updated about the latest tech trends.