Although many of us think of Messages as an iPhone app, Apple’s platform integration lets you read and reply to conversations in Messages on other Apple devices, including the Mac and iPad. All your devices must have the correct settings to make this work reliably. We regularly hear from users who don’t see all their messages on all their devices. If that’s you, check these settings:

• Same Apple ID: Your devices all know they’re yours when they’re logged in to the same Apple ID. That’s not a problem for most people, but couples who share an Apple ID, for instance, can run into trouble here. To verify this, open Settings > Your Name in iOS and iPadOS, or System Settings > Your Name in macOS. The email address under your picture at the top of each of those screens should match. If it doesn’t, scroll to the bottom, tap or click Sign Out, and sign in again with the correct Apple ID.
• Two-factor authentication: As with so many Apple services now, your Apple ID must be set up for two-factor authentication, which causes certain logins to be queried a second time on another device. Most people have two-factor authentication set up by now, but if not, turn it on using Apple’s instructions.
• iCloud Keychain: Your devices must have iCloud Keychain turned on to share your Messages account information. It’s probably already on, but you can enable it if not. Turn it on for an iPhone or iPad in Settings > Your Name > iCloud > Passwords and Keychain > Sync this iPhone. On a Mac, the switch is in System Settings > Your Name > iCloud > Passwords & Keychain > Sync this Mac.
• Messages in iCloud: This is the key setting—the previous three are just foundational requirements. Enable it for an iPhone or iPad in Settings > Your Name > iCloud > Show All > Messages in iCloud > Use on this iPhone. On the Mac, look in System Settings > Your Name > iCloud > Show More Apps > Messages in iCloud > Use on this Mac.
  
• iMessage account: You’ve checked that you’re using the same Apple ID everywhere, but there’s a similar setting that’s also important. On your iPhone or iPad, go to Settings > Messages > Send & Receive and make sure you’re signed into iMessage with the same Apple ID—look at the bottom of the screen. Also, ensure you’re set to send and receive from your phone number and appropriate email addresses. It’s safest to send and receive from all the possibilities and start new messages from your phone number. On the Mac, verify that you have the same settings in Messages > Settings > iCloud.
  
• Text Message Forwarding: Turning on Messages in iCloud should keep message history synced across all your devices, including green bubble SMS/MMS text messages. However, it’s worth verifying that SMS/MMS messages are being sent to all your devices. On your iPhone, in Settings > Messages > Text Message Forwarding, select all the devices you want to receive text messages.
  

Although all the above settings may seem like a lot, most should already be set up correctly. We listed them all because when people have trouble with their messages syncing across all their devices, one or more of these are usually set wrong.

Even with everything configured correctly, there can be hiccups—nothing’s perfect. If messages fail to sync consistently, try these troubleshooting steps:

• Use the Sync Now button in the Messages in iCloud settings on any device that hasn’t caught up. That likely won’t help instantly, but syncing should eventually catch up.
• Restart the device—it’s always worth trying. On an iPhone or iPad, choose Settings > General > Shut Down (at the bottom), slide to power off, and then press and hold the side (iPhone) or top (iPad) button to turn the device back on. On a Mac, just choose Restart from the Apple menu.

When Messages in iCloud is working properly, though, you can carry on text message conversations using any of your devices at any time. It’s especially nice to switch to the Mac for easier typing when you’re in an involved conversation.

(Featured image by iStock.com/anyaberkut)