Update file format used for updating AVG antivirus and security software; may be downloaded using the AVG TCP Server or AVGINET Lite programs, which download new updates as they become available; can be installed using AVG's Auto Update feature.

If CTF files become corrupted, the corresponding AVG program may not be updated. This problem can be fixed by running AVG's deleteupdatefiles.exe utility or by manually removing the CTF files and downloading the updates again. These files are typically named avginfoavi.ctf and avginfowin.ctf and are saved in the \ProgramData\avg8\update\download folder.