Beware of "cracked" keys found on social media or third-party sites, as these are often malicious or illegal . Review: Pros & Cons Ultracopier/ProductKey.cpp at master - GitHub

While the core software is free (GPL3 license), the developer offers an version. Ultracopier Ultimate Windows 64 - Google Groups

For critical data transfers (backups, archival, media production), Ultracopier can calculate and compare (MD5, SHA‑1, SHA‑256) of the source and destination files after copying. This guarantees that every byte was transferred correctly, protecting against silent corruption.