Good morning and thank you for posting on the Final Fantasy XIV Technical Support Forums.

Can you explain what you mean by DX9 mode "doesn't work?"

You can lower the settings or resolution in DX11 mode if your GPU is having trouble with it.

How often do you get the DX1100002 error when playing? Does it only happen in the Eureka areas?

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