Disk Space Analyzer

Answers the eternal question: "Where did all my disk space go?"

What it does

Windows tells you your C: drive is full but doesn't tell you why. Disk Space Analyzer walks through every folder on a selected drive, adds up the size of everything inside, and shows you the results three ways at once: a tree view (navigate the folders), a "top folders" list (biggest offenders first), and a "largest files" list (single files chewing through space).

The three views

Folder Tree

Mirrors Windows' file explorer. Each folder shows its total size and the percentage of the drive it occupies. Click to expand. The biggest folders float to the top.

Top Folders

Flat list of the 20 largest folders anywhere on the drive, regardless of how deeply nested. Great for spotting hidden space-hogs like C:\ProgramData\Package Cache or an app's logs folder you'd never have stumbled onto.

Largest Files

The 20 biggest individual files. Usually one or two Windows files (hibernation, paging), plus virtual machine disk images, large videos, or forgotten ISO downloads.

The summary panel

At the top you'll see:

Drive letter and label.
Total and free space, plus a colored usage bar (red if nearly full).
File system type (NTFS, FAT32, etc.).

How to use it

Go to Diagnose → Disk Space.
Pick the drive you want to analyze from the dropdown.
Click Scan. On a large drive this can take a few minutes on the first run.
Results appear in all three panels. Start with Top Folders.
Right-click any folder in the tree to open it in Windows Explorer or delete it.
Use Export to save the summary as a report you can keep.

Surprises to watch for:

C:\Windows.old — leftover old Windows install after an update. Safe to remove with Junk Cleaner after 10+ days.
pagefile.sys / hiberfil.sys — RAM-sized files Windows uses. Don't touch them unless you know why.
%LocalAppData%\Packages\ — Microsoft Store apps' caches. Individual app pages show what's inside.
System Restore — restore points can occupy 5–15% of the drive. Adjust in System Properties.

Don't delete folders you can't identify. If a folder name doesn't mean anything to you and it's in C:\Windows or C:\ProgramData, leave it alone — Windows probably needs it. Stick to your own folders under Users, or documented Windows cleanup locations.