: You should only ever right-click and extract part1.rar . The software (like WinRAR or 7-Zip) will automatically detect and pull data from part2.rar and subsequent parts to rebuild the original file.
: Use The Unarchiver from the App Store, as it handles multi-part RARs seamlessly where the default Archive Utility might fail. MacDowell_Sonatas.part2.rar
: You must have all parts in the same folder (e.g., part1.rar , part2.rar , etc.). : You should only ever right-click and extract part1