: Use a tool like WinRAR or 7-Zip . Right-click only on hitman_3.part01.rar (the first file in the sequence).
: This usually means Part 4 was corrupted during download. You will need to delete it and re-download that specific part. hitman_3.part04.rar
For a smoother experience with large multi-part downloads, many users on Reddit recommend using JDownloader 2 to automate the process and verify files. : Use a tool like WinRAR or 7-Zip