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Level 1

90 points

Your Mac was unable to communicate with your Apple Watch.

When I installed WatchOS 7 on my Series 4, I had terrible problems with the battery life. Usually when I put my watch on the charger at night, I would have about 50% battery left. After the update, my watch would last maybe 8-10 hours and then I'd start getting the 10% battery warnings. One of the solutions I found online was to unpair my watch from my iPhone and then pair it again. Doing this appears to have fixed the battery drain problem, but now I can not turn on the option to unlock my MacBook Pro with my watch.

To enable unlock with my watch I go to System Preferences -> Security & Privacy and tick the "Use your Apple Watch to unlock apps and your Mac." Sometimes I get prompted for my password to unlock my disk and sometimes I don't. In either case, "Turning on..." with a spinning icon is displayed for a few seconds, and then I get an error message from the subject of this post. It also says to "Make sure your Apple Watch is unlocked and on wrist, and your iPhone is unlocked."

This was working before I unpaired and re-paired my watch. I have tried all of the suggestions that searching for this error message brings up, including restarting everything, making sure everything is on the same WiFi network, disabling/enabling handoff, restarting bluetooth, disabling/enabling auto-unlock of watch from phone, logging my MacBook out of iCloud and back in again, etc. Nothing seems to help me get this option enabled again.

I would really like to get this option turned back on again. Any other suggestions?

MacBook Pro 15″, macOS 10.15

Posted on Sep 21, 2020 6:59 AM

Best reply

mark__t

Level 1

34 points

Posted on Sep 25, 2020 9:07 PM

This isn’t my solution but was posted in another thread by stoska992, but it worked for me!

I've finally fixed it! I found a bunch of errors related to "AutoUnlock" in the Console that was hinting to me that there was some invalid state on my Mac with keys and plists not being reset properly.

Steps (follow at your own discretion)

Open "Keychain Access"
In "View", enable "Show Invisible Items"
Search for "Auto Unlock"
You should see a whole bunch of application passwords for "Auto Unlock: XXXX's ..."
Select all records and delete (this will reset/disable auto unlock on other Macs if you use multiple Macs)
Whilst still in "Keychain Access", search for "AutoUnlock" (no space)
There should be 4 entries for "tlk" "tlk-nonsync" "classA" "classC"
Select 4 records and delete (don't worry if they re-appear, the system repairs this automatically)
Open "Finder" and navigate to "~/Library/Sharing/AutoUnlock"
There should be two files "ltk.plist" and "pairing-records.plist"
Delete both files
Open "System Preferences" and try enabling auto unlock. You may need to enable it twice, the first attempt will fail.

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384 replies

bsolberg

Level 1

10 points

Sep 26, 2020 12:55 PM in response to mark__t

Did all that and unpaired / re-paired several times and even factory reset my watch, but the problem is the same. No suggestions from MacOS to enable watch unlock, and trying to do so explicitly in System Preferences persistently gives the message "Your Mac was unable to communicate with your Apple Watch." So the problem continues to exist.

TiggerGTO Author

Level 1

90 points

Sep 26, 2020 4:00 PM in response to mark__t

In case my other response is not clear, the solution cross posted by mark__t that suggests to clear out the keychain entries and the plists is what worked for me. I had to restart before it worked though.

Sep 27, 2020 7:03 AM in response to mark__t

this solution seems to be working for me from my Watch Series 5 to my MacbookAir 2019. I did have to do a restart on the MacOS before the lock preference was enabled. Very convoluted work around, but well it worked. Thanks for nothing Apple.. Now onto the other zillion problems I am having with Watch OS 7 ....

Sep 28, 2020 5:18 AM in response to mark__t

I had this problem, after configuring a new Mac Book Pro with an Apple Watch I already own.

I assume that part of the problem was that I renamed my old MacBook to a new name and gave the new MPB the name the old one had before.

It seems that this confused the security mechanism and/id ID of the machine…

Any way following these instructions, I was abler to (re) activate the unlocking with my watch.

Sep 28, 2020 9:49 AM in response to TiggerGTO

Same problem except: my Apple Watch Series 3 works to unlock. My Apple Watch Series 5 does not. I too re-paired the watch 5 after the ridiculous battery drain. It solved that issue but the watch 5 will no longer open my Mac. I did not re-pair the Series 3 as its battery drain stopped after re-pairing the Series 5. Yes it makes no sense. Anyway I can unlock my Mac with the Series 3 but NOT with the series 5. I have tried the toggling of bluetooth and key chain edits and the plist things to no avail. It is interesting that when you delete the AutoUnlock items, they recreate themselves in just a few seconds so I'm not sure how effective that is. So the bottom line nothing so far seems to fix this Apple WatchOS screwup that keeps on giving. It would be nice to know the process involved with the watch unlocking so we would know what direction to turn.

Sep 28, 2020 11:03 AM in response to mark__t

This method is the only one that worked of the many I have tried. I noticed that there were quite a few duplicates of "tlk" "tlk-nonsync" "classA" and "classC", so perhaps that was the issue. Thanks!

Sep 28, 2020 8:49 PM in response to mark__t

This solution worked for me. I tried lots of other suggestions found on the web, to no avail.

On Series 4.

Same issue, unpaired/re-paired to fix battery drain issue in watchOS 7. Fixed battery drain to some extent, but could no longer unlock either of my Macs with watch (one on Mojave, the other on Catalina).

Thanks for the solution!

TiggerGTO Author

Level 1

90 points

Sep 29, 2020 10:46 AM in response to Frankbug

Did you follow the instructions posted by mark__t that I marked as the solution for this question? I know that I had to search for the ltk.plist and pairing-records.plist file in the Library folder in order to delete those. It also didn't work for me until I restarted my MBP. But, I I had previously tried just about every suggestion I could find for this problem, and I worked with a senior advisor who had me try reinstalling macOS. None of that worked for me. The answer submitted by mark__t is what fixed it for me.

Sep 29, 2020 11:17 AM in response to duZ3N

This solution did it. It took two attempts but the second stuck. Weird.

This happened after the iOS 14 update which killed the battery resilience of my AppleWatch. A un- then re-pair of the watch fixed that, but broke the unlock with applewatch functionality. Your fix did the trick.

Thanks for sharing.

Godaka

Level 1

4 points

Sep 30, 2020 3:28 AM in response to mark__t

I did this several times, rebooting the devices in between times. Nothing seemed to work. Went away from my macbook which had gone to sleep in the meantime. After logging in my mac prompted me to set up unlock with apple watch; I followed where it took me and it works!

Thanks!

Sep 30, 2020 4:00 AM in response to Rick Evertsz

Like a few others here, this solution suddenly stopped working. After a day of multiple reboots, going through the process over and over again, it suddenly worked. Hopefully, it continues to work. Clearly a bug of some sort.

TiggerGTO Author

Level 1

90 points

Sep 30, 2020 5:52 AM in response to bsolberg

@bsolberg, during the several weeks where this feature was broken for me, I tried this solution 2 or 3 times. Not only did it not work, but it caused me to have to add my credit cards back to ApplePay on my phone and my watch. I'm glad it worked for you though.

bsolberg

Level 1

10 points

Sep 30, 2020 7:08 AM in response to TiggerGTO

@TiggerGTO yes I had to re-enable ApplePay as well, but only had to confirm the security code of the cards I had on my phone and watch. Sorry to hear of your experience. I went through your solution several times with various permutations of rebooting in between steps, but never got to where the Mac would be unlocked by my watch. Looks like it did work for most of the people who have given feedback to the two threads I have seen on here for it though, and that is awesome. My follow-up reply was meant as something to try for those whom your excellent step-by-step instructions didn't work for.

What is really sad though is that a) this fails in the first place, and b) no better hints of the actual problem is in the system logs nor in the dialogue box. Takes away from the impression of robustness of the Apple products...

TiggerGTO Author

Level 1

90 points

Sep 30, 2020 7:21 AM in response to bsolberg

Thanks for the follow up, and I want to point out that the solution was not mine. @mark__t reposted the solution from another thread. I simply marked it as a solution for this thread.

On an interesting side note, I have tried to notify Apple that I found a fix through this discussion. Each time I have tried to update the issue via chat, they want to have somebody call me, probably because the issue got escalated to the point that I was working with a senior advisor directly on the phone. So far, all of the attempts that Apple has made to call me back have either happened at inopportune times, or I completely missed the call.

I think it is important to follow up with Apple, especially since the advisor walked me through collecting and submitting logs that he said he was going to send to engineering. Hopefully the combination of the logs and the solution that fixed the problem for me would be enough for a support engineer to create a fix in macOS for this problem.

Sep 30, 2020 7:33 PM in response to hakarlmedskyr

Likewise!! Extremely disappointed with Apple. I have tried Literary EVERY option, trick, tips and so called solutions for My Mac not communicating with my Apple Watch. All requirements met, Connected perfectly the first day of my new Macbook set up and Disconnected a day later! I've tried all updates as well. Nothing!

I have been having the worst experience with multiple apple devices lately with NO RESOLUTIONS! This Is Unacceptable!

Your Mac was unable to communicate with your Apple Watch.