My suggestion would be to disconnect the SSD & reboot the computer. Then turn off computer & put it back in. Turn back on & see what happens. Maybe the cloning software did something weird.
However, I'm at least 20 or 30 reboots, and several drive (both in some cases) disconnects past the final cloning.*
*THAT got interesting, so, I'll address it now:
Somehow Acronis makes the destination drive (the drive cloned TO) the boot drive, and BIOS / UEFI on this machine doesn't find the source drive as bootable at all, any more. IF the destination drive is still connected. The "old" drive is not shown, period. (Disk Management does show it, but of course can't assign a boot drive.)
So, what happened was, I originally cloned from the "old" 240 GB SATA SSD to the new 500 GB NVME drive. No problem, and, that left me with the 240 GB SSD still with the OS on it, available as "(E)", with plenty space left over for data. However, it's a very basic Sandisk drive, and, having read up on Crucial's MX500 series, well, those are just better all around, including better data security. For the money, only $34, I figured it would be much better as my quick-backup OS drive, plus data storage. But, when I cloned to it, then it became the boot drive and I could not change that to save my life. Until, that is, it hit on me to clone back from it to the NMVME drive.
Voila! Now the NVME is again my boot / programs drive (and the ONLY way to get the computer to boot off the MX500 drive is to pull out the NVME drive, as now UEFI / BIOS does not show the MX500 drive in any way shape or form.)