When i open the launcher it will tell me that i need to download the newest 1.11.2, which i have done multiple times. I then click download, but it brings up an error screen telling me this file already exists. Any Answers?

When I open the launcher it will tell me that I need to download the newest 1.11.2, which I have done multiple times. I then click download, but it brings up an error screen telling me this file already exists. Any Answers?