You cannot open or extract "m80.part7.rar" by itself. To extract the content, you must have all parts ( .part1 through .part7 ) in the same folder. Extraction Process: Ensure all 7 files are downloaded.
The software will automatically detect and join the subsequent parts ( part2 through part7 ) to rebuild the complete file. If you are missing a part, the extraction will fail. If you can tell me: m80.part7.rar
Use a file archiver tool like (Windows), 7-Zip (Windows), or The Unarchiver (Mac). You cannot open or extract "m80