Hi, second move was to install LinuxMint 18.1 who saw the win10 and allowed me to install it as dual boot, giving some sdd space for every OS. Afterwards i plugged the old HD and nothing was lost. I...

The first thing needed would be to unplug the 1tb drive 7 was installed onto. Apparently the 10 installer may have already tried placing boot files as well as one or two temp installation folders...