how to restore all setting lost by update

Yes - I have backups - it turns out what works is the following

1. boot into recovery (option command R)
2. got to utilities and erase the boot drive
3. reinstall the latest OS
4. on startup then restore from backup
5. It takes a long time - but works

You get your system updated to the latest OS and restored with your previous settings.

Note; this only happens if your home directory is on an external drive.

My other Macs with the home directory on the boot drive had no issues with the upgrade - just my 2 iMacs with external drives for the home directory.

This has happened on two iMac that has remote drives for the user directory.

Having to wipe mac and restore from backup to restore the setting - takes hours.