Kingeds wrote:
You need do good preparation before upgrading system to Windows 8.1. Then there will be no data loss. I did not know this before I upgraded my XP to 8.1, I then lost files. To rescure them, I got Windows Boot Genius to help me at last!
It depends on what you're upgrading from. From Windows 8, you lose very little, but from XP you lose quite a bit.