RE: Optiplex 9010 Intel Management Engine BIOS Extension (MEBx) option disappears after selecting from BIOS.
Thank you so much SpeedStep. It looks like a BIOS update was necessary. After updating to A24 for this box, it resolved my issues. In fact, the BIOS level was A05! I incorrectly noted BIOS to be A14 (from the other boxes in the lab). For some of the boxes, I also needed to CMOS reset for some reason to get the admin password reset. Since these are second hand boxes a complete BIOS update was necessary as well in addition to the CMOS reset.