OK, I'm a recent addition to the list of people having problems with this. MS must think it's a non-issue though, as I've been experiencing this for two days (June 26 & 27, 2016) since I did the "upgrade" (actually I'm convinced Win10 is not an "upgrade",
but that's another discussion).
I upgraded Windows 7 Pro to Windows 10 Pro, running on a Samsung 850 evo SSD. I used Samsung's Magician software to clone the drive, so the problem is not solely related to Macrium.
This is not a traditional "dual boot" with multiple OSes running off one drive. I have the Samsung SSD as the Win 10 boot drive, and dual WD 2TB Black drives - one containing a Windows 7 Home Premium install, and the other contain data files.
I have had to go back and forth a few times, and it has not been fun or pleasant. The problems started yesterday with chkdsk wanting to run (I think on the Data drive) and that was relatively benign, but I could live with it.
Today, I not only got the chkdsk problem complaining about "extended attribute set" and "reparse point" problems, but the system completely failed to boot into windows 10. The boot drives are set to to check C:\, and the SSD was hooked to the board's SATA
array in position 0 (zero) as one would expect.
I got into this unrecoverable error state where it wanted to do a system recovery (I didn't allow it to proceed). I THINK it was so confused that regardless of Windows 10 being in position 0 as the primary boot drive, it was trying to boot windows 7, or
at least the error stuff had a light blue background with a white bird as found in Win 7/ 7 Pro.
The system finally booted into Windows 10, but only after I disconnected the Windows 7 drive from the SATA array by unplugging the cable. I don't know what to expect and I'm afraid I will have to pull the Windows 7 drive to use Windows 10.
I think there may be something being set on the drives, or perhaps there's a BIOS problem. Windows 7 boots into a "legacy bios" on my machine and Windows 10 boots with UEFI secure boot. The two are not compatible as far as I know but I can't understand
why even having the other drive on the array is an issue since only one is bootable.
What an unacceptable mess they've created!!!! No amount of nonsense like running
DISM.exe /Online /Cleanup-image /Scanhealth AND/OR
DISM.exe /Online /Cleanup-image /Restorehealth
is ever going to help anything. That's the worst answer I can think of right now..