Your Apple Watch must be signed in to iCloud to allow it to unlock your Mac.

Unpairing and repairing the watch did not help.

Here's what i've tried:

• on Mac open System Preferences > iCould > Account Details > Devices Devices, select Apple Watch and click Remove From Account
• restart iPhone
• open Apple Watch app on iPhone
• open General > Apple ID
• I saw my Sign In button below my Apple ID
• then i accidentally went back to General and after going to Apple ID again the Sign In button was not longer there!

Come on, Apple, you've got improve the quality control of software that you release!

I went through the exact same thing. Signing out and back in to iCloud on my Mac eventually allowed me to tick the box. However, now it says "unlocking with apple watch" and then times out and I need to put in my password. Working through this issue now...

I had this problem too. Tried everything, un-pairing watch, switching off and on hand-off, updating iOS, updating watchOS, nothing worked until I updated my MacBook Pro to 10.12.3 (just came out in the last few days) and then it worked on first try. This leads me to suspect it's not a watchOS or iOS issue but a macOS issue. Hope this helps.

PS I said I tried updating my watchOS and iOS, those updates just came out in the last few days too, so maybe just make sure everything is up-to-date.

This worked for me. Nonunpairong or standing on your head.

Problem appears to be when you turn off two value authentication and enable two factor authentication your phone and Watch get "disconnected" from iCloud.

Solution: Go into Settings-Messages on iPhone. You most likely are likely fed out of iCloud and only receiving messages from your phone number. Tap Sign into iCloud. It will ask if you want to use your current signed in account. Tap ok. It will stay gray for a bit (no activity indicator) and then all your addresses will show up that you can send and receive messages. This seemed to also kick my watch to connect to Messages as a new Apple Watch, FaceTime as a new watch I then went back to system preferences on computer, checked Apple Watch to unlock, put in my password, and after a few minutes it connected (there was a spinning indicator that it was adding or connecting).

Bauhaus10 wrote:

I had the same problem after I had changed my icloud/apple password. It was resolved after I logged in into www.icloud.com.

I got this problem after changing my password and opting to logout all my devices. My other devices all prompted me to login and then told me on all the devices that there had been a login. Lots of "ok"s! Plus I was prompted to login to Apple store on all the devices as well. I also have two factor identification.

But my Watch never prompted me to login; naively, I assumed it was good if my iPhone that's paired with it was logged in again. However when I realized Apple Watch wasn't letting me login on my Mac any more, I checked System Preferences and found the check mark was cleared from the box allowing apple watch to unlock my Mac.

When I checked it and saw the error about need to log my Watch into iCloud, at first I just thought, huh? Then I looked in the Watch app and found that under General / Apple ID, I saw I wasn't logged in. So, I logged in thinking, ok, that should do it. It took a really long time to get it logged in. When it finally was, I thought, I'd be good to go, but System Preferences still wouldn't let me do that.

I came here and found the suggestion to pair and unpair the watch and that finally worked. It took a while but it restored everything except I had to enter some credit card info again. I have a Watch 2 and I don't think it took 45 minutes, but 20-30 maybe? It was mostly up and working except for installing apps and adding the complications for them in about 20, perhaps.

Oddly, about an hour later, when I started writing this note, I noticed that the check mark had disappeared from the "Allow" box in System Preferences. No idea why, but I put it back in and it took first try.

- Liz

Well, I had this happen again. This time, I just rebooted my Mac (for other reasons), and it started working again. This time, the check mark did not disappear.

At the time, I was also having problems with App Store on Mac, iPhone, and iPad; they all appeared logged in but were not able to update any more. I had to log out of each and then log back in again to fix that. That shouldn't have anything to do with my Watch unlocking my Mac, but at this point, who knows?

Just to report that this bug is still a problem in watchOS4.0 and macOS Sierra 10.12.6. I had to change my Apple ID password, and even though I was logged into iCloud with the new password, System Preferences refused to allow my watch to unlock the Mac because it claimed I wasn't logged into iCloud.

I had already un-paired and re-paired the watch earlier in the day and wasn't eager to do it again, but restarting the Mac fixed the problem.

FWIW, unlocking with Apple Watch (watchOS4.0) and my iMac (late 2013) now running macOS 10.13 has been working flawlessly since updating from 10.12.6 to 10.13. So much so that I had forgotten it had previously been an issue.

I am also suddenly since yesterday suffering from the same issue. MacOS 10.13.2 and WatchOS 4.

Two factor authentication is on. I tried a repair of the watch, rebooted the Mac and watch but settings on the Mac is still telling me my watch is not signed into iCloud when it is.

Nothing has changed in my setup that could be causing this. Aaaargh 😠

OK, so I'm not losing my mind. I'm seeing the same problem. I have a Late 2015 MBPr (macOS Sierra 10.12.1), iPhone 7 (iOS 10.1), and an Apple Watch 2 (watchOS 3.1).

My Apple ID is set up with two-factor authentication, and working fine on all devices. Both the MBPr and iPhone are connected to my N network at home, and Bluetooth is enabled. My Apple Watch 2 is on my wrist and turned on.

I get the expected Turning on... spinning cog:

Then I get this error:

I tried turning Handoff off and back on, didn't fix it.

I tried setting the iPhone to Airplane Mode, and making sure the Apple Watch 2 is connected to my Wi-Fi network, didn't fix it.

This started happening after the 10.12.1 update was applied. ¯\_(ツ)_/¯

TIA,
Don

Same problem here, just started happening after the most recent update. I've signed out and signed back in to iCloud on both my phone (and thus watch) along with my Mid 2014 MBP.

I have the same issue on a brand new (refurbished) Macbook Pro 2015. Can't turn on the Apple Watch unlock feature. I'm also running 10.12.1.

How do we fix this?

I solved the problem by unpairing then repairing apple watch.

I also fixed it at this point, it was much more painful than it needs to be though:

Sign out of iCloud on all devices (please note that this will delete Credit/Debit cards on Apple Pay which is annoying). Sign into iCloud again, turn on the unlock feature, reboot all devices and it will work.

Nice feature though, it's super fast - glad I went through the trouble to activate it.