I have a Lenovo Yoga 64 bits with CORE i7 and just updated my operating system to Windows 8.1 today. Here are the problems that have be stuck with me for the entire day:
My touchpad scrolling no longer works. It's Synaptics. Whatever solution that worked for other people did not work for me, some of them I didn't even have the same options
There is no sound, either playing aloud or from earphones
My iTunes doesn't work. Despite the no sound problem, the progress bar bar doesn't even move.
I am yet to discover more problems (yeah for me!) on my laptop after the update. By the way, are these problems just here because most programs aren't compatible with Windows 8.1 yet?