13n.7z.001 -

: Select "Extract Here" or "Extract to [Folder Name]" from the context menu. Common Troubleshooting

: Ensure all sequential files (ending in .002, .003, etc.) are in the same directory as 13n.7z.001.

: You cannot extract the data using only the .001 file; you must have all parts of the sequence in the same folder to successfully rebuild the archive.

: Ensure all parts have the exact same base name ( 13n.7z ) before their numeric extension; otherwise, the software will not recognize them as a single set. How to Extract .7z.001 files - Microsoft Q&A

: The ".001" suffix means the original data was too large for a single file and was split into multiple volumes (e.g., 13n.7z.001, 13n.7z.002, etc.).

: If the extraction fails with a "Unexpected end of data" error, you are likely missing one of the numbered volumes in the sequence.