ZIP is an archive file format that supports lossless data compression. This file, like other archive file formats, is simply a collection of one or more files and/or folders but is compressed into a single file for easy transportation and compression. However, some users on Mac OS are getting an error when they try to double click the zip file to unzip. The error message they get is “Unable to expand filename.zip (Error 1 – Operation not permitted.)” and it is shown with the Archive Utility dialog.

What Causes Unable to Expand Zip File?
We investigated this particular issue by looking at various user reports and the repair strategies that were commonly used to troubleshoot and resolve the issue by users finding themselves in a similar situation. Based on our investigations, there are several different scenarios that are known to trigger this particular error message:
- The download file is damaged – When you are downloading files in a browser on Mac OS, there’s a chance that the file might not be downloaded correctly and completely because of closing the websites before the downloading completion. Whenever this happens, you will be unable to open the zip file, even though the file might be present in Download folders. In this case, you can resolve this issue by downloading the file again without closing the downloading website or by downloading through Terminal.
- Zip file containing a very large file – Another Potential case in which this error occurs is when unzipping (decompressing) a very large file. Several users finding themselves in a similar situation have reported that they managed to resolve the issue after using Terminal with the unzip command to expand the zip file. Because Archive Utility doesn’t allow you to unzip large files.
- Permission on the zip files – In some case, the permission to read/write or directory of the zip file can be responsible for this particular error. If this scenario is applicable, you can resolve the issue by using the 3rd party software to unzip the files.
If you’re actively looking for ways to resolve this exact error message that is keeping you from using zip files, then this article will provide you with a list of quality troubleshooting steps. Down below, you’ll discover a collection of methods that other affected users have successfully used to fix this particular problem.
Method 1: Unzip File by Using Terminal
When the simple double clicking zip doesn’t work, you can always try to unzip the files in Terminal. Sometimes the large size files are unable to decompress in the Archive Utility and it needs to be decompressed in Terminal. There is a simple command “unzip” used in the Terminal for the zip files, to make them unzip. When you use this command the file will go to the user account folder. To unzip a file in Terminal, follow the below steps:
- Hold Command and Press Space to open Spotlight, type Terminal to search and Enter
Opening Terminal through Spotlight - Now try the unzip command for your zip file
unzip filename.zip
(You can drag and drop the zip file, so it can paste the directory too)
- Press Enter and it will start unzipping
Decompressing the zip file in Terminal - For most cases, if you get No such directory Error or cannot find, you can manually use “cd” command to get into the directory and unzip from there, Like this:
cd Desktop unzip timer.zip
Using the cd command to change directory and then unzip in Terminal
If this doesn’t solve the issue for you, then don’t worry, you can try the next method below.
Method 2: Using Decompression Utility Software
Now sometimes there can be problems with your permissions or opening of zip file normally. But there are many Utility software on App Store and online, which can help you unzip the zip files without any issues. You can download the Stuffit Expander from the Mac App Store and try using that for the zip file. Most of the users were unable to unzip files even by using Terminal but using this software helped them fix the problem. You can check the steps below for how to unzip using this application:
- Open Mac App Store by clicking the icon in Dock
App Store on Mac OS - Now search for the app “Stuffit Expander” in the app store
- Click on the Get and then Install, this will install the application on your Mac OS
Installing the Stuffit Expander on App store - After installing, click open or go to Spotlight (Command + Space) and search for “Stuffit Expander”, then open it
- Now, click on the Stuffit Expander Icon of application
- Locate the zip file that you want to unzip and open
Unzipping the zip file through Stuffit Expander - Then choose the folder where you want to unzip it to
- This will unzip the compressed file for you.