Simple File Verification file - used to verify the integrity of a set of files, this is a text file containing file names and typically CRC32 checksums. For Windows, try a program such as QuickSFV or fsum to verify the integrity. Mac OS X users should try MacSFV. Normally these files should not be necessary with BitTorrent, since the BT protocol has its own error checking method (on top of TCP's checksumming.) If you find some file that doesn't match the checksum in its SFV file, blame the torrent's creator, since he or she should have fixed it before creating and distributing the torrent.