With your name not returning in Help > About, and your issues building rescue media there's something not quite right. If it was me I would re-install Macrium.
Okay, well, I re-installed, rebooted, and tried again. Report, as always, was Rescue media successfully built. But it wouldn't work on either of my machines. Got to thinking about the loading windows as MR prepares to write the rescue disk. On my working 7675 MR, as the write RM starts, it says writing xxx of 800+ MB. On my installs of 7771 and 7762, I noticed that it said writing xxx of 700+ MB. That struck me as a glitch, even though MR reported success in building the USB RMs.
I think, though I don't know, that the "boot" folder that Macrium builds during the installation plays a role in building the RMs. I compared the boot folder on my 7675 machine with the boot folder on my 7771 (and, earlier, 7762) machine and found that on the machine that successfully builds RMs, boot was the same size and size on disk, while on the machine that couldn't build an RM successfully, boot was considerably different in size (huge!) and size on disk (much smaller). On the supposition that the boot folder was involved, I deleted the boot folder on the 7771 machine (had to take ownership first, to delete it) and then opened MR and went to the Rescue disk panel, and found "WIM not found. Build to repair." When it finished, I checked and found that the new boot folder had size and size on disk equal, as on the working machine.
Next step was to reformat a USB drive and try again, and then to test the disk. It worked perfectly. Tried it on my other machine, and it worked there, too.
Someone will probably tell me that this was all more luck than skill, but I won't mind. MR 7771 is now on both my machines, and is able to rebuild RMs on both. The new installation didn't work, but the new "boot" folder (
and things associated with building that folder from scratch, probably having to do with the Windows Boot Manager boot files on my C: disk) did it.