Have a nice little Intel NUC for my wife’s PC.  It has a 500 GB SATA SSD which is getting filled up, mostly with photos.  I thought I would make use of the PCIE m.2 slot so I bought a 1 GB drive to replace the old SATA.  Should be a quick disk clone, like I have done dozens of times.  Even easier now with these free utilities you can download.

Well, it took two hours to copy all the files for the clone, then I couldn’t get it to boot from the new m.2.  twiddled with the BIOS, plugged and unplugged drives in various combinations.  Tried a different clone tool.  Then I read that some Intel NUCs will only do a new style UEFI Boot, which is a new secure format for boot, on the m.2 drive.

Found a way to convert the new disk to UEFI.  Suddenly it showed up in the UEFI BIOS list, but various tweeks to BIOS settings didn’t help.  I could see all the right partitions and all my files, just no way to get it to boot.

One way  forward was to try to convert the old SATA drive to UEFI, then clone it.  But this disk is essentially an original MS-DOS 5.0 system that has been upgraded over the decades.  I didn’t want to risk damaging it.  Thought about buying a second SSD to close it for safe keeping, but that seemed like too much work and expense.  I guess I finally gave up and decided to just make the m.2 a second data drive and keep the SATA SSD as it is for boot.  So much for UEFI and secure boot.