Recently my Apple watch stopped opening my MBP. After some investigation I found the solution on Apple’s support site. This solution worked for me. I thought I’d pass this along to save others time if they run into a similar problem.
- 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.
- Shut down and restart the computer
