This is a bug, you have released an MSI that is unable to properly do it's job. I had to go dig for the file and clear it myself. This is the level of quaality that Riot aspires to right here. What's next, it can't properly install? Might as well throw in a virus to keep LoL on my machine - oh wait, you effectively did.
I went ahead and report League to my antivirus and other antiviruses to save people the trouble. It might not mean much but it's the most effective tool I have to publicly recognize the Riot, Inc. virus known as the "Alpha Client."
I went ahead an deleted registry keys that Riot should have uninstalled because I want that startup time back. I do not recommend you doing this, but Riot's product quality (or lack thereof) prevented me from the correct solution.
