I got told the acronis backup got booted in legacy mode all the time. By accident it got booted in UEFI mode, which resulted in an short error message (dissapeared too fast to read) and instantly rebooted, leaving Windows 10 stuck at the rotating circle. It usually booted into the boot menu selection "Win10 and Win7" after a short Win10 circle screen. All peripherals have been removed (1 wireless mouse), which is one common issue regarding the circles too. Auto repair doesnt help and forcing Win7 to boot via the advanced menu works. Its one HDD (SSD) and everything is visible. Win7 and Win10 parition. "bootrec /scanos" says it has "0" OS installed. Will either "bootrec /fixmbr" or "bootrec /fixboot" be a good idea on this dual boot system ?