A ZIP file looks like a neutral box, but it records details about each file you put in it. The most revealing are the dates: the archive stores the time each file was last saved, so a recipient can see which files you edited late at night, which you touched yesterday and which have not changed in years.
What a ZIP stores
- The last-saved date and time of every file, to the second or two.
- The names of files and folders, which can include people’s names and project names.
- An optional comment for the whole archive and one for each file.
- The files themselves, each with its own metadata, which a ZIP does not remove.
Why it matters
A bundle of documents sent to a regulator, a client or a journalist shows a working pattern. Dates can also contradict a story: a contract that claims to have been drafted last month, inside an archive where it was saved last week.
How to clean a ZIP
- Clean the files first. A ZIP does not change what is inside them: use the Image, PDF or Document tools on the contents.
- Pack them into a new ZIP.
- Run the archive through the ZIP Metadata Remover. It sets every file date to the same fixed value, deletes the archive comment and file comments, and leaves the files byte for byte unchanged.
File names are your job
The remover does not rename files, because names are content. Check folder and file names for personal details before you zip. A folder called with a client’s surname tells the recipient who the client is.