peerManager is missing

My iMac (OSX 10.12.2/10.12.3) won't reboot.

I don't think this is a 10.12.3 problem because the machine was acting flaky in the same way before the upgrade, but I had always been able to reboot it. With the upgrade, I cannot.

The problem(s):

1. on reboot there is no chime

2. during standard reboot, the apple logo with progress bar comes on. when progress bar is full, nothing else seems to happen

3. on reboot recovery mode (command-R), that worked. I recovered my system from a TimeMachine backup.

4. on reboot single user (command-S), that worked. I did "fsck -fy" twice. Then tried "exit". After lots of error reports, machine finally just hung and reporting repeatedly (about every ten minutes): IO80211Interface::update Report _peerManager is missing.

What do I need to do to get my iMac straightened out.