Ensure your destination drive has enough free space to hold the final, combined file. Troubleshooting: "No Archives Found" / Corrupt File
You must have all parts ( .part1.rar , .part2.rar , etc.) in the same folder.
If you get a "no archives found" or corruption error, you can attempt to repair the archive using WinRAR's built-in repair tool:
Click on the file, hold Alt and press R (or click the 'Repair' button in the toolbar). Save: Choose a location to save the repaired file.