Use The Unarchiver or Keka , as macOS does not support RAR files natively.
For the extraction to work, you must have of the archive (e.g., part1.rar , part2.rar , part3.rar , and your part4.rar ). ekspres4k.part4.rar
You should never try to extract from "part 4" directly. Always and select "Extract Here" or "Extract to [Folder Name]". Windows users: Most people use WinRAR or 7-Zip . Use The Unarchiver or Keka , as macOS