You must delay the upgrade, see:
http://esupport.sony.com/US/p/os10upgrade.plBruno
>I upgraded my VAIO notebook from Win 8.1 to Win 10 Pro.
>
>Overall impression is good, but it seems to start a little slower than Win 8.1.
>
>Wanted to watch some videos from MVA but did not get a usable result. New video player and Edge only showed the left half of the screen. The right half was not recognizable. In Firefox got sometimes good video but not always.
>
>Reading some forums it seems the problem shows up on different hardware and is partially not there when using other browsers like Chrome.
>
>Went back to 8.1.
>As a little nuisance I had to reestablish to network connection but otherwise all is ok and I did not loose anything.
>
>Will try again next year.
>
>Hope this prevents some others from having the same experience.
>
>Gerhard