Login screen keeps appearing after sleep. System Prefs doesn't fix. High Sierra

It does work correctly in the other account. I can modify the delay to lock screen.

Screenshot of 'com.apple.systempreferences.plist'

So it would be user specific.

You lost me there.

My two options:

1- Download BBEdit and change the '6' to number of seconds till the screen locks.

2- Or re-dump the .plist and restart all the while keeping the Preference Pane open.

So I found the culprit line <key>com.apple.SecurityPref.Privacy.LastSourceSelected</key>

<integer>5</integer>

However the value is 6.

So I should delete the entire file "com.apple.systempreferences.plist", or its contents? Then restart to re generate the proper code?

Using TextEdit the file opens to gibberish. What is BBEdit? And what value should the integer be?

So I took the plunge and removed the file, restarted the Mac but the problem persists.

Now have the following within the 'systempreferences.plist' :

A previous post [https://discussions.apple.com/thread/8222805] the fellow had a similar problem but the thread terminated with a call to Apple Support. The OP didn't follow up and on what was done. Not helpful here.

Somewhere in the forum there was also another attempt by removing the .plist file, but I can't locate it. It didn't work but perhaps another solution was found.

BTW, no settings changed in my System Preferences, all the same as before the dump.

Strange as this Screen Shot of the previous .plist was very populated:

Tried a few variations. Still immediately locks screen after a display sleep (hot corners).

So after a reboot with the original file (the long one) and added a 60 sec delay, the delay went to "0".

As I'm going nowhere with this and it doesn't seem to work, would a re-install of High Sierra override the troublesome file(s)?

It's a painfully long process, but I can always re-download dosdude1.com patcher. I didn't use the patcher but the 10.13.6 download.

I replaced the current user plist with the secondary user account plist but there is no change.

A sreenshot after re-boot:

I still cannot change the delay in my Prefs.

I had trashed and emptied the plist prior to the re-boot - I kept a copy in my Mail.

I'm hitting the sack - early morning hours here. Will take it up Tuesday after work. I'm GMT-4:00

I should add that this OS is not a clean install and integrated my former version of 10.8.5

Also, my locked screen is not the typical blurred background but the former textile grey (previous OS?)

So the BBEdit is only for v.10.14 & up.

So I changed to 1800 seconds (30 minutes) but the screen still immediately locks.

And the 'Require Password xx' still remains unresposive.

I'll try again with the newer (dumped) version...