MCL will not launch when the .minecraft folder is already existent.

Yesterday I wanted to launch Minecraft Java but it wouldn't launch. I looked up the issue, the only things I have found worked, but like I said, it will not launch when the .minecraft folder exists. I would be able to launch MCL, login, and then run Minecraft. After it launched though, and created the .minecraft folder, MCL would not launch again. I tried to put MCL for the version, but it did not work.