Okay, so yesterday I was rolling in a party to fight Benkei. We made it to where he had just a decent chunk of life left, then extreme lag kicks in. I suddenly get DC'd and crash. So I'm about to re-launch the game (along with being ticked off) only for the launcher to suddenly pop up in Japanese. Since I had no clue what was going on, I let the update bar get full then closed it

Today I have tired to open the launcher and nothing happens. So I am forced to uninstall then reinstall the game. So I'm not really happy about this and would like answers.

It's an issue with the game's launcher utilizing the same cache as the Japanese version's game launcher. It'll bring up the wrong cache (the japanese version) and of course show the Japanese version of the launcher and function as if it were the launcher for that version. Since you don't have the Japanese files it'll download them (repatch) which replaces your en files in the process but since your client/launcher is intended for the the en version after it's finished "repatching" it'll find an error when checking the files and thus won't allow you to play since the files are "wrong. It'll then proceed to wipe those unwanted files (I think) and thus'll leave you annoyed at the very end. (yay. =.=)

Well, that's the long explanation of roughly what happens. (bit of guessing here and there, but according to what I know, that's about what happens)

Anyhow the only temporary solution we have as of the moment is to just keep a backup folder with the .pkg files and replace them whenever this issue occurs.