Can’t open a zip on Mac (error 79 or error 1)

When Finder says Unable to expand “file.zip” with error 79 or error 1, Archive Utility couldn’t read the file. The number is a macOS error code: 79 means Inappropriate file type or format, 1 means Operation not permitted.

Error 79: the file isn’t the zip it says it is

The download didn’t finish. A cut-off zip can’t be read. Download it again, and check its size against the size the site shows.
It isn’t a zip. Some sites send a web page or another archive type named “.zip”. In Finder, select it and press ⌘I: Kind says what it really is.
Archive Utility doesn’t know the format. Try another reader (below).

Error 1: macOS stopped the write

Archive Utility wasn’t allowed to write where it unzips, usually next to the zip. Move the zip to your Downloads or Desktop folder and try again, or check you can create files in that folder.

Other ways to get the files out

Terminal, built in: tar -xf file.zip (it also opens .rar and .7z), or ditto -x -k file.zip folder.
The Unarchiver or Keka, both free on the Mac App Store.
Whizra: select the zip and type unzip it (unzip it with password 1234 for a locked one). It uses a different reader from Archive Utility, opens .rar and .7z too, and if it can’t open a file it says why in plain words.

Questions

What does error 79 mean on Mac?

It’s macOS error code 79, “Inappropriate file type or format”: Archive Utility couldn’t read the file as a zip, most often because the download is incomplete or the file isn’t really a zip.

What does error 1 mean when unzipping?

It’s macOS error code 1, “Operation not permitted”: Archive Utility wasn’t allowed to write the files where it unzips them.

Can a Mac open .rar or .7z files?

Not with Finder. Terminal’s tar -xf can, and so can The Unarchiver, Keka or Whizra.

Checked: 3 Nov 2026.

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