FBA 2012 Neo Geo core generates .fs files in the root of hdd

Hello all. I have RetroArch in the E:\Emulators\RetroArch\RetroArch folder and the roms in the E:\Emulators\Neo Geo\Neo-Geo Romset folder. If i play Metal Slug ,for example, when i quit RetroArch a file msulg.fs is generated in the root of my E HDD. I’m using the fbalpha2012_neogeo_libretro core. How can i fix this? I don’t think it’s normal…

Thanks!!