We are using Civil 3D and Autocad 2012. One of our machines is havinf a font problem. Text styles are set to simplex, and they change appearance by themselves to Arial., even theough the style is til set to be simplex. This is the first time I've seen this happen and I don't know why it happens. The style command can be used and change the styles to be romans, and the text looks fine. Close Autocad, reopen, open the drawing and the fonts are whacked to Arial, the styles still call for romans. Not every letter either, but most. Change the styles back to simplex font, everything is fine. Close Autocad, reopen, open the drawing and the fonts are whacked again. What causes this, and how do we fix it?