DWG format to DXF -> .DXF file is empty

Hello everyone,

I would like convert .DWG file to .DXF file, so I do "save as" and I choose Autocad 2013 DXF and OK. The problem is that when I try de close and re-open this file, the size was reduced to approximately 40Ko (~2000Ko at the beginning...) and my plan disappeared. I don't know if I am clear. If I don't please tell me.

I hope you could help me.

Thank you

Regards