Good morning and thank you for posting on the Final Fantasy XIV Technical Support Forums. We apologize for the delay in our response.

You mentioned that you turned off DirectX 11 mode, then reenabled it. Do you mean you turned it off then immediately back on, or that you tried to start the game in DX9 mode?

Double check that your anti-virus has the appropriate exceptions for the game (these can be changed if either programs update).

If the above does not work, try reinstalling the game. Make sure to delete the XIV files from the 'My Documents' folder (My Documents > My Games > Final Fantasy XIV) as these are not deleted when you reinstall the game. If you can, reinstall the game on the C Drive if it is not already.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!