A file with the .001 extension, such as , is a split archive file typically created by 7-Zip or other compression tools like WinZip . This specific naming convention indicates it is the first part of a larger, multi-volume 7z archive.

For the archive to work, you usually need all subsequent parts (e.g., PA02.7z.002 , PA02.7z.003 ) in the same folder. How to Open PA02.7z.001

: Use 7-Zip (free and open-source) or PeaZip .

: Ensure every numbered part of the archive is in the same directory. If a part is missing, the extraction will fail.