FOSS gamedev and creative worlds

First of all, hi there ! It's my second post here LOL
So, my Minetest client ir crashing frequently and after it crashes, the world dissapears. idk what's the matter, i didn't mess with the game...
Any help here ?

OS?

Windows 7 Professional

Edit minetest.conf with a text editor; replace the line with "video_driver = direct3d9" with "video_driver = opengl", without quotes.