A "rarreg" file is the specific registration key file used by WinRAR to verify a paid license. A key generator (or "keygen") claims to be a tool that can manufacture these files for free.
Another powerful, free tool with a clean interface for extracting and creating archives. The Bottom Line Rarreg key generator
Pirated files often lead to corrupted software and frequent system crashes. Safe and Legal Alternatives A "rarreg" file is the specific registration key