Reference
Where the space usually goes
The layers the Folder Scan sorts files into, what each usually is, and what is usually safe to do about it. Your computer's maker has the last word: their guides are linked at the end.
- Video
- Phone videos, screen recordings, downloaded films. Usually the thickest layer. Moving older videos to an external drive or cloud storage frees the most space for the least effort; keep a second copy first.
- Photos and images
- Phone photo imports and camera RAW files (.cr2, .nef, .arw, .dng) are large. Duplicates are common after importing the same phone twice.
- Installers and disk images
- .exe, .msi, .dmg, .pkg and .iso files in Downloads. Once a program is installed, its installer can usually be downloaded again from the maker. Keep any you could not get again (old licensed software, drivers for old hardware).
- Mail data and backups
- Outlook data files (.pst, .ost), mail exports and backup images. Leave these to the program that made them: never delete a .pst or a backup file you have no other copy of.
- Archives
- .zip, .rar and .7z files. A zip next to a folder of the same name has often been unpacked already; open both and check before removing either.
- Code and developer folders
- node_modules, .git, virtual environments and build folders. Project tools can usually rebuild dependency folders, but only clear them in projects you are not working on.
- Documents
- Rarely the problem: even thousands of documents are usually a few GB. Keep them.
- Music and audio
- Music libraries, podcasts, voice recordings.
- Everything else
- Game files, app data and files without a known extension.
What the scan cannot see
Browsers do not let a page read a whole drive, system folders or other people's folders, so the Recycle Bin or Trash, system restore points, hibernation and page files, app caches and updates do not appear. That is why the logbook uses the drive's free-space figure for the forecast: it counts everything.
The makers' own tools
- Microsoft: Free up drive space in Windows
- Microsoft: Manage drive space with Storage Sense
- Apple: Free up storage space on your Mac
- Apple: Optimize storage space on Mac
How a page reads a folder: showDirectoryPicker() and webkitdirectory (MDN). DesktopService.net is not connected with Microsoft or Apple.