Malicious actors repackage old versions of File Centipede, label them as "Pro Full Version," and distribute them on warez sites. These versions are intentionally crippled to appear as "Trial Mode" to trick users into downloading a keygen or activator—which is almost always malware.
Even though File Centipede is free, the developer still incurs costs for domain registration, hosting, and development time. While no activation code is needed, you can: file centipede activation code full