Alex Ruben
How To Resolve Error 79 Inappropriate File Type on MacBook 2025 During Unzipping
If you’ve run into Error 79 while trying to unzip files, yeah, it’s annoying. Basically, your Mac gets confused about what kind of file it’s working with, and sometimes it just refuses to unzip. Not sure why it works sometimes, but it’s worth trying a few tricks before throwing in the towel. Let’s walk through some methods that helped me and others fix this without much fuss.
Method 1: Use The Unarchiver App
Why this helps
This app is pretty much a lifesaver for opening tricky zip files that Finder or Preview can’t handle. Sometimes, default macOS tools won’t decompress files that aren’t perfectly formatted, or are slightly corrupted. The Unarchiver is more lenient and supports a ton of formats.
When to try this
If you double-click and get Error 79 or similar, or the usual unzip methods just stall or give weird errors, then it’s time for this. Also, if you’re noticing that some files refuse to unzip with Archive Utility, switch to The Unarchiver—it’s free, by the way.
What to expect
Once installed, you can open your problematic zip with it, and chances are, it’ll get the job done. Sometimes you may need to set it as the default app for zip files to avoid repeating this step.
Steps
- Open the App Store (click the Apple menu and select App Store).
- Search for The Unarchiver in the search bar.
- Download and install it. Usually, you’ll just click Get and then authenticate with your Apple ID.
- Navigate to the zip file, right-click, then choose Open With > The Unarchiver.
- If you want, right-click the zip, select Get Info, and under Open with, set The Unarchiver as default, then click Change All.
In my experience, it’s weird how it sometimes takes a second or two for it to process — on some setups it works immediately, on others, it seems like reboots help. Of course, macOS likes to make things more complicated than they need to be.
Method 2: Check File Integrity and Format
Why this helps
Sometimes, Error 79 isn’t about the app, but the file itself. It could be corrupted during download or transfer, or maybe it’s a weird format or incomplete archive. Ensuring your zip file is legit and intact can save a lot of headache.
When to try this
If the same files keep failing no matter what app you use, or if they’re from suspicious sources, check the file.
What to expect
If the archive is corrupted, redownloading from the source might fix it. Or, if it’s just a bad zip, opening it on Windows or another machine can help diagnose if it’s really usable.
Steps
- Try re-downloading the file from the original source, just in case it’s incomplete or corrupted.
- Verify the file extension matches (should be .zip or similar). If it’s some other format, you might need a different tool or to convert it.
- On some setups, you can run terminal commands like
file YourFile.zipto check what kind of file it is, orunzip -t YourFile.zipto test the archive without extracting.
On some machines, this alone clears up the error after confirming the file isn’t broken, then retrying extraction.
Method 3: Check macOS Settings & Permissions
Why this helps
Sometimes, macOS permissions or security settings block certain files from being processed, especially if they’re from unknown sources. Adjusting these can make a difference.
When to try this
If everything else seems fine, but you still get errors, especially with files downloaded from the web or email attachments.
What to expect
Adjusting permissions might allow the system to access and unzip files normally again.
Steps
- Navigate to the folder with your zip, right-click, then select Get Info.
- Under Sharing & Permissions, make sure your user account has Read & Write access.
- If permissions are restricted, click the lock icon, authenticate, and then change permissions to allow full access.
- Sometimes, running a terminal command like
chmod -R 755 /path/to/your/folderhelps, but beware — only do this if you’re comfortable with command line.
This isn’t a guaranteed fix, but sometimes permissions get funky after macOS updates or file transfers. On one setup it worked, on another, still no luck. Because of course, macOS has to make it harder than necessary.