XOFTspy Portable Anti-Spyware is a proprietary application developed by ParetoLogic Inc. for Microsoft Windows computers. The anti-spyware program is designed to run from a USB drive and protect users from malicious threats. While the software is free to download and scan, the user must purchase a license to clean. The license is valid to clean multiple computers from the same U3 USB drive.Portability can be useful in situations where a computer is heavily infected, bogged down, or sluggish.