SFV (Simple File Validation) is used for checking consistency in files. We expect all users, especially f-servers, to check all of their files using the SFVs. Corrupt, incomplete or failing files can not be served.

We recommend using hkSFV to check your files. You can download it here.

hkSFV is the simply the easiest, most intuitive and automatic way to create or check .SFV and .MD5 files. And, of course, it's completely free.
What is an .SFV? -- An .SFV file is a tiny list of files and CRCs, which allow you to check to see if the files you have downloaded are exactly what you are expecting. The CRC algorithm used in .SFV files allows you to see if the file you have has been changed, even a single byte, since the .SFV file was created.
What is an .MD5? -- In a sense, .MD5 did not exist until now, as md5sum is a popular Unix format similar to .SFV and Unix does not use file extensions the way Windows based systems do. .MD5 uses the md5 algorithm to compute its checksums, rather than the crc32 method used by .SFV. The md5 algorithm is almost as fast as crc32, but it is much more accurate at detecting changes in files.
If you need to ensure that your data or data you download is error free, this program is for you.
If you've got an .SFV or .MD5 file, this is the program for you.
If you'd like to create an .SFV or .MD5 file, this is the program for you.

The fastest way to check an .SFV file is to put it in the directory of the files you wish to check, and double click it. This will launch hkSFV and it will automatically verify your files. You can also run hkSFV and then use File|Open to verify and .SFV.

If the files have different filenames than what is in the SFV and you wish the the program to find the renamed files, click Tools>Find Renamed Files.

The SFV will rename your files on the default setting. To stop this, click File>Preferences. Click the "Checking" Tab and change the Renaming option to "none".