Combine unzipped xml files back into a working XLSX file

I can rename an Excel file extension from .XLSX to .zip and extract out the xml files.

How do I combine individual Excel xml files back into a single XLSX file?

I tried zipping up the folder and renaming the .zip extension back to .XLSX but then Excel has a problem opening the file.

Solution 1:

Found it! Seems I was zipping up the entire folder, you need to zip up the three folders and XML file:

_rels
docProps
xl
[Content_Types].xml

Then rename the zip files extension to xslx and it opens fine.