If you run Stardock Windowblinds then please uninstall it before performing an upgrade installation of Win 10. If you don't then a vertical taskbar configuration may get corrupted.

This happened to me and in Win 10 a vertical taskbar takes up half the screen. A horizontal taskbar at bottom of the screen works normally. Even after uninstalling Windowblinds, my win 10 did not support a vertical taskbar.

WindowBlinds does not yet support windows 10 anyway so just go ahead and uninstall it before updating.