These days, a relatively clean and uncomplicated Windows 10 system disk might be home to more than 150,000 files and 90,000 folders. A more complex, application-heavy system disk might contain between half a million and a million files. That’s a lot of files!

Indeed, not all those files need be kept around. Thus, it’s a good idea to practice disk hygiene on a regular schedule. That’s exactly what’s explained and explored here, with plenty of examples and screen shots to illustrate the cleanup process. Best of all, the tools that’ll help you tidy up won’t cost you a dime.

Step 1: Run Disk Cleanup or “Free up space now”

From time immemorial, Windows has included a utility for cleaning up disk space — namely, Disk Cleanup, a.k.a. cleanmgr.exe. In Windows 10, users gained a second method to clean up disk space, part of its Settings-based “Storage Sense” facility, which is aimed at optimizing storage in Windows 10. Though there has been speculation that the first method might disappear as a result, the Disk Cleanup utility remains ready, willing and able to work even in the latest 19H1 Insider Preview (Build 18317) as I write this story. Either approach provides a great way to clean up extraneous and unneeded Windows 10 files.

To launch Disk Cleanup, type disk or cleanmgr.exe into the Start menu search box. Either way, the Disk Cleanup desktop app should appear at the top of those search results. Be sure to right-click the program and select Run as administrator from the resulting pop-up menu. Why? Only then will it offer to clean up redundant or outdated OS files (such as old OS files after an upgrade, or old updates) as well as other Windows leftovers. After Disk Cleanup scans your system, this screencap shows a reasonable facsimile of what you’ll see when it fires up: