Because this is part of a split archive (indicated by .part1 ), you generally cannot open it successfully without having all the other parts (e.g., .part2.rar , .part3.rar ) in the same folder. What is this file likely for?
Based on common naming conventions in file-sharing communities: RP3.part1.rar
: Right-click on Part 1 only and select "Extract Here." Because this is part of a split archive (indicated by
: Many users share PlayStation 3 game files split into parts to bypass upload limits on hosting sites. RP3.part1.rar
: Ensure you have downloaded every numbered part in the set.
: Large asset packs for custom roleplay servers are often compressed and split this way.