: If you encounter a similar error message like "Can not open file as archive" while manually using 7-Zip, it often means the file's start or end headers are damaged. Expert users sometimes use hex editors to repair these headers .
The "Non-7z archive" error typically occurs when a software installer, specifically for programs like or ChemOffice , is unable to properly extract its component files using the 7-Zip compression format . Why This Error Happens
: Delete the installer file you previously downloaded to ensure no corrupted data remains.
: Download a fresh copy of the installer and run it again. Alternative Causes
: This clears any temporary processes that might still be trying to access the old installer files.