1. Open your launcher.
2. Click on Config (top right icon).
3. Repair Installation
solution #3: (confirmed by one person on US)
1. move your RADS folder out from LOL directory, try running patcher.
Info from RivingtonThe3rd:
Some things that have been working for people:
- Run as administrator
- Give the patcher some time to run
- Do not click during League of Legends logo
- Be sure to install to C:\Riot Games
- A lot of people seem to be fixing their issues by updating things such as drivers, NET framework and windows updates, please let us know if going through this process allows you patch and play correctly.