You cannot open part .003 on its own. You must use a tool that can "stitch" them back together:
Download it from the official site, 7-zip.org . Once installed, right-click on the first part ( .001 ) and select "Extract Here."
A free file archiver for extremely high compression Brought to you by: ipavlov. SourceForge
...and any subsequent numbers until the end of the sequence. 2. Use Extraction Software
Choose your destination folder to receive the full, uncompressed "feature" or content. 7z.001 7z.002 7z.003 help please - SourceForge
These paid alternatives also support multi-part .7z archives. Unzip One: A free option available for Windows users. 3. Extraction Process Place all numbered parts into a single folder. Open your extraction tool and navigate to that folder.
Right-click specifically on the . The software will automatically detect parts .002 and .003 to complete the extraction.