At the beginning of each game, my HUD is completely transparent. I have to train my first skill before my skills appear, and have to open the store before my item/gold area appears. My teammates portraits are also blank. Throughout the game, the portraits will randomly fill up. This has been happening for the last couple of months.
Guster Posey2 votesYou mean like this? http://imgur.com/ABsibZT
The Wreckuiem1 votesYes, like that. It changes from game to game which things are completely invisible, but it's usually everything. I've noticed that sometimes Alt+tabbing will make things go invisible again after they've appeared. 
iDelude1 votesThe new league HUD was supposed to provide more "clarity" 
and all that snazz , right? I don't think clarity translates into, for the most part, complete transparency
iDelude2 votesI've been having the same issue, it just started occurring yesterday though. It's tolerable, but rather annoying.
Guster Posey1 votesI had support help me out, they sent me a special folder for installing a new version of league, as well as they found new Graphics Drivers which fixed it for me. Ask them to reference ticket #17819460, this is the ticket that fixed it for me.