Ah.part4.rar - Bayfiles -

However, since you're looking for an regarding this type of file, 1. The Art of the Multi-Part Archive

A file ending in .part4.rar is a "split volume." You cannot open it alone; it is a single piece of a larger puzzle. AH.part4.rar - BayFiles

: Use the "Keep broken files" option in WinRAR if you are desperate, but it's better to re-download the specific part (in your case, Part 4) to ensure the data isn't corrupted. However, since you're looking for an regarding this