The core scan-to-cleanup sequence
- Pick a scan target Choose a drive, a user profile folder, or a specific directory. Scanning the whole
C:\drive gives the full picture, but scanning justC:\Users\YourNameis faster and covers the folders most people actually control. - Start the scan Launching the scan begins a read of every folder under the target. This step only reads directory information; nothing is moved, changed, or deleted while it runs.
- Let it finish A full system drive can take a few minutes, especially the first time, since nothing is cached yet. Folders with millions of small files, like package caches or source trees, are the usual reason a scan runs long.
- Switch the size column if needed Confirm whether the results are showing logical size or allocated size. The two can disagree noticeably on drives with many small files, and switching between them changes which folders look heaviest.
- Sort by percent of parent This is the single most useful column for a cleanup. It tells you what share of the folder above a branch actually consumes, so you can tell at a glance whether opening that folder is worth your time.
- Drill down the heaviest branch Open the top folder, then its top subfolder, then the one below that. Stop as soon as you reach individual files rather than folders — that is the point where you have actually found what is taking up the space.
- Switch to the chart or treemap view A treemap turns the same data into colored rectangles sized by disk usage. It is useful for spotting one enormous file hiding inside an otherwise unremarkable folder, which is easy to miss in a plain list.
- Act on what you found Delete, move, or compress the files responsible — but only after you are sure what they are. Our guide to deleting large files safely covers the judgment calls this step involves.
Right-click actions and shortcuts, in general terms
Right-clicking a folder or file in the results typically exposes actions like opening it in File Explorer, deleting it, or excluding it from the current view. These options save you from switching windows constantly while you work through a tree.
- Opening a folder's location in File Explorer lets you inspect file names and dates before deciding anything, which matters more than the size number alone.
- Excluding a folder from view is useful when you already know a branch is safe (a game install, a media library) and want the remaining list to focus on what you have not checked yet.
- Refreshing a single branch after a cleanup is usually faster than rerunning the whole scan, since it only re-reads the part of the tree you just changed.
System folders and other users' profile folders may not be fully readable, or deletable, without administrator rights. If parts of a scan appear unexpectedly empty or an action is blocked, see running TreeSize as administrator.
Reading the columns without misjudging a folder
Three numbers show up over and over in the results, and mixing them up is the most common source of confusion for first-time users.
- Size is the sum of the logical file sizes inside a folder — the same number File Explorer's Properties dialog reports.
- Allocated space reflects what the file system actually reserves on disk, which can run noticeably higher than logical size on a drive full of small files.
- Percent of parent measures a folder's share of the level above it, not of the whole drive, so a folder can show a high percentage while still being small in absolute terms.
If a folder's reported size looks wrong compared to what File Explorer shows, check which of these three values is currently displayed before assuming something is broken. Persistent mismatches, empty branches, or scans that hang are covered on troubleshooting.
A first cleanup in ten minutes
- Scan your user profile folder rather than the whole drive, to keep the run short.
- Sort by percent of parent and open the top three folders in turn.
- Note anything obviously safe to remove — old downloads, duplicate installers, video exports you already uploaded elsewhere.
- Switch to the chart view once to catch any single oversized file the list view buried.
- Delete only what you clearly recognize, leaving anything unfamiliar in
AppDataor system-managed folders alone for now. - Rerun the scan on just that folder to confirm the space was actually recovered.
Ten minutes will not clear a drive that has been neglected for years, but it reliably finds the easy wins — the files that are large, obviously disposable, and safe to remove without research.
Questions about using TreeSize
Do I need to scan the whole drive every time?
No. Scanning a specific folder is faster and is usually enough when you already suspect where the space went, such as a downloads folder or a project directory.
Why does the scan seem to stall on one folder?
Can I pause a scan and resume it later?
What is the fastest way to find one huge file instead of a huge folder?
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