Apple watch won't open computer
For some time, my Apple Watch (A1978-4th Gen) successfully opened my MBP (13,3) running High Sierra 10.13.6) without typing in my password.
Within the last few days, it has stopped opening the computer. It waits briefly (1-2 seconds), then I have to put in my password manually.
I have gone to preferences>security and privacy, turned off "Allow your apple watch to open your Mac", restarted, turned it back on, restarted and then slept the computer. It still doesn't work.
I have not installed any system updates in either the computer, watch or associated iPhone.
Any help? What might I try next?
MacBook Pro 15″, OS X 10.11