Preventing booting

[Sebastian42]

I run my x32Win10ProV22H2 in a desktop with an extra internal drive for accepting downloads. I clone the system every week to two separate drives, as well as to a partition on a larger drive. All drives are 2.5" SATA SSDs - all internally connected, but the clones have switchable power, so are only accessible if I switch the power to them on. This arrangement worked well for years, until only my system drive and one of the 'separate' drives would boot. The failure to boot shows by the PC hanging in 'Verifying DMI Pool DATA'. After much expenditure on new drives and much trial and error, I can again boot from all three clones (as well as my system) but NOT as previously. The clone on the partition and the clone on one separate drive will boot only if I disconnect the extra internal drive (which is a new drive with NO read errors). Having tested a dozen other 2.5" SATA SSDs, I finally found one 'extra internal' (that DiskSentinel had described as having 0% Health condition) that allows ALL the drives to boot - it accepts downloads and videos on it can be played. I would not usually need to access that extra internal drive when I boot from a clone, so it is no great inconvenience, but it is an intellectual challenge as to what could cause this phenomenon.