Boot fail (not BSOD) error "security_initialization_failed" (no codes)

Hi Brink and all at TenForums,
I find this error on a google search, but not on this forum, but always have seen quality from these forums. Soooo my trusty home brew build, stable for 8months, running Win10, had also been following a routine of boot drive image backup and creating maintenance boot dvd's between Win 10 version upgrades. today booted as normal, POST is fine Win10 hourglass begins, runs circa 5 seconds, then a blue screen (not BSOD, the Win10 variety with "" on it. The error is "SECURITY_INITIALIZATION_FAILED" (verbatim with the error, including Caps and underscores", but no normal, but non-sensical, hex-code to go along with it. One further sentence of info follows, saying "You can reboot" and "you can search for the error". Cool reboot came back to the same screen. Second cold boot I had "Automatic Recovery Starting", but hung shortly after". My "Boot Recovery Disks" generated from Control Panel, won't boot, with the good old DOS "Non-system disk or disk error".

I haven't yet fully taken in the issues / tried standard fixes, this my first "reaching out" for help. Hoping for a fast-track to resolution at best, how to get to my boot-image on the second hdd, at worst!

Thank you in advance, if I have any joy inbetween, will update

(apologies for posting to this forum, but not quite sure where it sits, because of "security" error, non-BSOD etc)

If I was you I did reinstall Windows