WizTree is a disk-space analyzer that turns a drive or folder into a size-ranked tree, a file list, and a rectangle map. It reads file-system records, totals the space under each folder, and makes unusually large files visible without opening them. File Explorer can show the size of selected items, but it does not build the same whole-drive inventory. WizTree reports where storage went; it does not decide which files are safe to remove.
Read the tree
The tree view adds every file beneath a folder and sorts the result by size or allocated space. Opening a branch explains which subfolder produced the total. The file view can group extensions, filter names, and expose large items that sit several levels below an ordinary user folder.
The treemap draws the same inventory as nested rectangles. A large rectangle means that one file or folder accounts for a large share of the selected space. Color and position help reveal clusters, but the map does not explain ownership. A large database, virtual disk, or package cache may belong to an active program, so the path and containing folder need inspection before any removal outside WizTree.
Size has two meanings
WizTree separates logical Size from Allocated space. Logical size records the amount of file data. Allocated space records the disk clusters reserved for it, and each file occupies whole clusters. Many tiny files can therefore consume more allocated space than their combined logical sizes suggest.
Compression, sparse files, and hard links complicate the comparison. A hard link gives one set of stored data another file-system name. WizTree marks the extra link so it does not count a second physical copy. Treating every visible name as independent storage would inflate the total.
The allocated total can still sit slightly below the Space Used figure shown by the operating system. NTFS keeps directory indexes, security information, and other structures that occupy the drive without appearing as ordinary files. That difference does not mean WizTree missed a hidden folder, and repeatedly rescanning will not make the two figures identical.
The fast path
On an NTFS drive, WizTree can read the Master File Table instead of asking the file system to enumerate every directory. This path produces the familiar fast scan, but it requires administrator rights. Without that access, WizTree must use a slower method. A user who dismisses the permission request can still receive a result, yet the scan may take noticeably longer.
Scanning a single folder and scanning an entire drive also create different evidence. The Master File Table record number works as a unique file identifier only when WizTree exports a complete NTFS drive scan with administrator rights. A partial folder export cannot safely use that number as a permanent identity.
Save the evidence
WizTree exports the selected view to CSV with file names, logical and allocated sizes, modification times, attributes, and folder counts. If nothing is selected, the export covers the entire current result. Filters can include or exclude paths and file patterns, which makes the export useful for comparing a known set of media, archives, or virtual disks.
A treemap can also become an image, while a complete scan can become an MFT dump. WizTree can load saved CSV or MFT data later, so an old inventory remains available after the live drive changes. The saved data is a snapshot rather than a monitor: it does not update when a file grows, moves, or disappears.
