.QUA File Extension

File created by Avira AntiVir, an antivirus application; saves an infected file in an encrypted format so that it cannot be opened manually; used for quarantining files that contain viruses.

Avira AntiVir quarantines infected files by encrypting them and moving them to a safe location. When the software downloads an update that can clean a particular file, it removes the virus, decrypts the file, and moves the file back to its original location.