Ensure B1.part1.rar and B1.part2.rar are in the same folder.
Right-click only B1.part1.rar and select "Extract Here" or "Extract to...". The software will automatically read part 2 to complete the process. B1.part2.rar
If part1 is missing, you cannot extract part2 . Ensure all parts are downloaded fully. Ensure B1
Use software like WinRAR , 7-Zip , or The Unarchiver (for Mac). B1.part2.rar
Use The Unarchiver or B1 Free Archiver to handle split .rar files. Troubleshooting
Here is a report on how to handle, extract, and troubleshoot this file: Technical Overview Part 2 of a Multi-volume RAR Archive.
Once I know this, I can tell you exactly which tool you need to open it. How to Extract Part .RAR Files (Full Guide)