I upgraded customer PC from 7 to 10 due to a HDD failure.
Luckily, I was able to backup data to my workshop PC (Windows 7).
So on the customer PC, I installed a new HDD, installed windows 7, activated & did most updates, then upgraded to windows 10
Since the HDD was new, I decided to then do a clean install of Windows 10, after which, it re-activated after skipping the registration key prompt… so far all normal.
To speed up restoring customer data, I typically remove the HDD from a new system (in this case its a Windows 10 PC), attach it to my workshop Windows 7 PC (using SATA), copy the customer data to the Windows 10 HDD, then re-insert the Win10 HDD into original PC…
But each time I tried it, data would disappear, or was only half was visible, or I would get boot errors & all sorts of corruption.
After re-installing Windows 7 & doing the win10 upgrade 3 separate times, I eventually decided that windows 7 just cannot handle the Windows 10 file system
So, after much frustration, I just copied the customer data from the workshop PC to an external USB drive, then copy the data to the Win10 system via the USB
Now I need to ask myself: how long will I wait before upgrading all my work PCs to windows 10?