Well, this is embarrassing. I'm the topic starter, didn't get any pings that anyone had answered, so I didn't check back! Thanks for all the input.
Security is a nightmare on this phone. I'll try the solutions suggested above. In the meantime, I can't for the life of me get any of three security options to work for me:
- Fingerprints: I've deleted and re-entered them twice. Once or twice they've actually worked to open the phone. The other dozens of times I've tried, they don't get recognized. I angle my thumb differently, I press harder, I lift it and start over. It just. Doesn't. Work. Eventually I have to resort to my pin.
- Trusted location: the change to the situation above is that, when I tried to enter my home address again on the other email address on the phone, I got a message that it was already entered as my home address. It seems to keep that information in common across accounts. What it doesn't mean is that it will work. It still doesn't keep the phone unlocked.
- Password: I deliberately make my passwords intricate and difficult to guess. I finally got tired of entering it again and again and again. I've resorted now to a simple 4-digit pin. I dread what could happen if this phone falls into the wrong hands.
So yeah - not really impressed with this so far.
I tried downloading old, trustworthy Finger Security. The fingerprint sensor is built into the front-page graphic. Bizarrely - even though it's turned off in the settings! - the Samsung fingerprint sensor pops up on top of it! And of course it doesn't work. So I'm back to entering the pin.
Again - I'll try the various suggestions above, and thank you. Now I'll go figure out why subscribing to this post didn't work! Maybe I'm carrying around some vexing electrical field ...