: If any parts are missing or named differently (e.g., one has a space and the other doesn't), the extraction will fail with an "Unexpected end of archive" or "Volume missing" error.
: Use a tool like 7-Zip or WinRAR and right-click specifically on Part 1 . SiMo15.part2.rar
Are you getting an when trying to extract, or are you missing some of the other parts? How to Extract Part .RAR Files (Full Guide) : If any parts are missing or named differently (e