Your Mac was unable to communicate with your Apple Watch.

This worked perfectly. There's a missing "on" in the first step--I ended up turning "Keychain" off then restarting the Mac. After I restarted it, I got a notification prompting me to allow the Watch to unlock! Perfect. I then went back and turn "Keychain" back on and now everything seems to work.

Thanks for the help!

Well, I wasn't having any luck having tried every single step listed in this forum multiple times. So, I checked for some updates to my Mac OS. I am running Mojave and had turned off all updates because this computer is used for professional audio production. To my surprise there were a couple updates... security and supplemental. Once my iMac rebooted after install, the first thing I tried was to enable the unlock with Apple Watch. It immediately worked... so fast in fact that I didn't think anything had actually happened. I logged out and re-woke the display... my watch logged me in faster than I've ever experienced. I hope this info helps those who are getting nowhere with the suggested troubleshooting.

I am now running MacOS Mojave 10.14.6.

I had to try the "KeyChain" solution several times. After deleting the files and rebooting my computer, it didn't work. I deleted files, stayed in, and tried pairing two times. The second attempt was successful, so keep trying!

ccfromatl wrote:

I'm trying the solution from mark_t, but can someone direct me to where the "Keychain Access" is? I don't see anything in System Preferences besides a checkbox for Keychain that fits.

Applications -> Utilities -> Keychain Access

You can also use Spotlight (command-space) and start typing "keychain" and it should find it before you finishing entering the word keychain.

This worked for me. I found using finder to get to sharing was annoying so I just used terminal. Be sure that terminal is granted full disk access or you won't be able to enter the Sharing/Autolock directory to delete the files.

The instructions here worked great for me. However, unlocking my MacBook with my watch will not work all the time. The setting is now correct, but the function doesn't work the whole time. My wife has the same issue, and she has never had the issue that her Mac was unable to communicate with her Apple Watch. Does the function to unlock with the Apple Watch require some Apple (online) service to be available?

I'm afraid that the problem has become intermittent. With the last WatchOS (7.1) and MacOS (10.15.7), the watch will not always unlock my MacBook. Without me changing anything, the watch will work at other times.

This is my experience as well - updated Watch, iMac & iPhone & it worked for 2 days & now doesn't even though everything is the same.

Apple really need to fix this issue as it's very frustrating.

This didn't work for me, until I *also* signed out and back in to iCloud on ALL devices (including iPhone the watch is tethered to). Not sure if the above solution is what did it, or the iCloud restart, or both -- but *solely* the Keychain & Library deletions didn't do the trick.

I have tried this - more than once - with and without reboot but no resolve.

Also I see this in the syslog:

Nov 13 11:21:00 jonass-5k-imac com.apple.preference.security.remoteservice[20503]: objc[20503]: Class AWDSecurityPrefAutoUnlockSetup is implemented in both /System/Library/PreferencePanes/Security.prefPane/Contents/XPCServices/com.apple.preference.security.remoteservice.xpc/Contents/MacOS/com.apple.preference.security.remoteservice (0x1037b0768) and /System/Library/PreferencePanes/Security.prefPane/Contents/MacOS/Security (0x106343770). One of the two will be used. Which one is undefined.

To me this seems like an issue with migrated configurations (was using latest Catalina before this).

Hope for a patch soon.

Hey everyone, after upgrading to Big Sur, my Apple Watch Series 6 stopped being able to unlock my MacBook Pro. I did all these steps and it didn't work. I just unpaired my Watch from my iPhone XR and repaired it and it started working.

I had the same issue and tried all of the troubleshooting steps with no luck. I called Apple support and they wanted me to logout of iCloud and change my password. I logged out and then simply logged back in and then got it to work without having to change my password.

I had this problem after updating to Big Sur (iPhone X and Watch Series 3). I tried all of the suggestions here and elsewhere online to no avail. What did work for me was to reset my default keychain:

1) Open Keychain Access on Mac

2) Open preferences within Keychain Access

3) Click on "reset default keychains" and let it do its thing.

4) Restart Mac

5) Reactivate the "Use your Apple Watch to unlock apps and your Mac" within System Preferences. (It might take a couple tries to engage.)

Again, this did the trick for me after nothing else worked. This does erase all of your saved passwords within your keychain, but it doesn't take long to get things back up and running if you have your passwords for iCloud, Mail, etc. handy.

Thank you very much mtgags. I tried resetting but this did not work for me but it led me to a solution that worked. I restored an earlier ~/Library/Keychains from a Time Machine backup and it worked perfectly. Thank you again.

I had this issue before and back then the deletion steps outlined here a couple of times (keychain items etc) worked back then, but this time they didn't.

A simple log out of iCloud on the Mac and back in did the trick this time.