I had issues with a Focusrite Liquid Saffaire 56, using windows 7 64bit, and bought then dearly when it was just out on the market. Focusrite was very helpful and even sent me a personal special Firmware version to install via some DOS routine .com or .bat file. Sold it later and alas dumped the software stuff LoL. Switched to RME BTW, never regretted the step, but had some issues with windows 10 64bit recently. Windows 10 is a fast booter, but it's definitely still problemous regarding USB and Firewire .... I couldn't get firewire to run on windows 10 64 bit with my UFX, legacy drivers or not, had to use USB. F