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

I had to repeat every single one of your steps to get this to work. Thank you. It's such a strange bug!

I agree that re-pairing is not an option. It's not just an hour of waiting. The problem is that payment cards in the wallet are not backed up. So in my case it means calling in to several banks and passing security checks to re-activate the full wallet. Not something I'm going to repeat any time soon. We need a fix now.

Are you sure you still have to do security check? All my apple pay/wallet items do not require security check anymore. Just use iPhone to "scan" credit card and enter CVV and it's done. No more calling the bank to authorize and etc. I agree, still painful tedious but much easier than phoning in a call to BOA and etc.

I don't know why, but it's working again.

I haven't updated anything or repaired apple watch

It's not that streamlined in Canada. It requires extra verification. Some are now done through an e-mail code or a separate app with bank login, but some still require calling in to phone support.

After spending an hour or so and failing to enable it, even after rebooting the iMac and watch, my unlock suddenly started working when I came into the office the next day. Didn't re-pair the watch, either.

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

Remember when Apple's thing was that it all 'just worked'. Good times.

I'm currently having the same issue. I set everything up so the watch would unlock my MacBook Pro and it was fine for exactly one unlock. Then I got the same error message as you, literally about an hour after that first use.

Having checked that the watch was indeed logged into my Apple account, I tried restarting all my devices, but that didn't work. I'm now in the process of re-paring my watch, which is slow and not at all fun, to see if that fixes it.

Having experienced similar things with Apple Pay (worked once, has never worked again) it seems like Apple just really need to get their crap together.

Thank you! This was my 1st roadblock. In case you guys have my same second road block. Delete all your bluetooth connections, turn bluetooth off and on. And you should stop seeing the prompt for a password on waking from sleep. Watch unlock still prompts for password

Same here. I posted in this thread about giving up getting this working, but lo and behold, I came back from lunch today and my iMac unlocked itself !?

The Mac hasn't been restarted since last week, and the only major difference I can think of is that my Apple Watch ran out of battery power over the weekend. However, restarting the apple watch had been part of my previous troubleshooting steps weeks earlier, and had no success.

Oh well. Happy user here.

and now, a day later, it has stopped working again.

Trying to turn it on again on the iMac and I get the same "your Apple Watch needs to be signed into iCloud.." message.

W.T.F.

unpairing and repairing did not work. and it took 45 minutes 😟

I updated my Apple Watch (1st gen) to watchOS to 3.1.1 and my work iMac to macOS 10.12.2 this morning, and auto unlock is now working.

Thanks, Apple!

Exactly the same issue: I have 2 mac (MacBook 12 2015 & MacBook Pro Retina 2015) + Apple Watch 2 + iPhone 7 (all on latest OS / fully updated).

It all works for few days before it stops on at least one of the 2 mac.

Yes un-pairing and re-pairing the watch fixes it (albeit for a few days only) but it does take ages...

This is a BUG which makes the whole unlock with apple Watch function totally useless : when will Apple fix it ???

Same issue for me. Frustrating as this was a great feature when it's working. Hope Apple gets this fixed soon.