Last Updated on March 3, 2024 by Dave Farquhar
The other day my son was working with a Zip file and getting frustrated. He was trying to delete a large number of files from it, and the CPU went to 100% usage and never finished. Here’s how I got him around the problem of high CPU usage with Zip files, or Windows Zip folders being slow.
The problem with slow Zip folders and high CPU usage
The Zip folders functionality built into Windows Explorer works fine for basic operations like creating and extracting files. For complex operations, it’s not always ideal. By complex operations, I mean removing or overwriting files from the middle of an existing file. If all the files you want to change are grouped together it will usually work. But if the files are randomly spread out throughout the file, you’re likely to see the problem my son ran into, getting 100 percent CPU usage and hanging.
It’s an 80/20 product. It provides the core 20% functionality that you need 80% of the time, but struggles when you need to do something harder.
It’s frustrating, because this doesn’t seem like something that should be hard. A 4.77 MHz PC/XT running PKZIP under MS-DOS did stuff like this just fine when I was about his age. It seems like a 3.7 GHz Intel i7 should be able to. There are ways, of course.
The workaround for Windows 100 percent CPU usage with a Zip file
To fix the high CPU usage problem took a few steps. First, I pulled up Task Manager by hitting CTRL-ALT-ESC and scrolled down to Windows Explorer. I right clicked on Windows Explorer and selected End Task. Then I went to File > Run New Task, typed explorer.exe and clicked OK.
Restarting Explorer like that helps prevent recurring issues. It’s like a mini reboot but it’s much faster.
Next, I extracted the Zip file to a new folder. Then we deleted the files he needed to delete, replaced the files he needed to replace, and built out the folder the way he needed it.
When he was happy with the layout, I right-clicked the folder and selected Send To > Compressed (zipped) folder. No problems.
Yes, it’s a workaround. But it worked fine.
Another workaround for Windows 100 percent CPU usage with a Zip file
Of course, there’s another workaround. You can just use a third-party Zip archiver like WinZip, WinRAR, or 7-Zip. It’s not as convenient. And then you have a third party piece of software you need to keep up to date. But it’s more reliable. It’s like installing Microsoft Word when you outgrow WordPad or Notepad.
If you can get by with the functionality built into Windows, fantastic. If you can’t, don’t torture yourself. Install the better program.
Why not upgrade the CPU?
Of course some people argue if you run your CPU to 100% on a regular basis, it’s time for a new CPU. Some software will use up all of your CPU no matter how much power you throw at it. The Zip folders in Windows has always been one of those things. The PC I use at work is a 10th-generation i7 with 32 GB of RAM, and it will fail with the same operation.
It’s not the CPU in this case. The code is more than 25 years old at this point, and it’s single threaded, so it will never use more than one CPU core. Dave Plummer, the original author of the code, said so much in a tweet in March 2024. His recommendation? Use Winzip or 7-Zip if you’re hardcore about your zip performance.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.