If Part 04 specifically shows a "Checksum Error," it means that specific file was corrupted during download and needs to be re-downloaded. Why Is It Split into 2GB Segments?
You cannot "open" part 4 individually. You must initiate the extraction from Part 1 . ER_2GB.part04.rar
Many file-hosting services have a 2GB file size limit for free users. If Part 04 specifically shows a "Checksum Error,"