aSpaceScan is a free, open-source disk space analyzer for Windows 10 and 11. It finds what is filling up a drive. On NTFS it reads the Master File Table directly, so a whole drive, a 10 TB one included, is mapped in seconds.
A folder tree with size bars, percentages and file counts; file types, and the same totals grouped into categories; the largest files, and search by name, size or age; a duplicate finder with the space you would get back.
Every scan is stored automatically, so a scan can be compared with an earlier one to see what grew. Delete, copy and move from the results, several items at once. HTML and CSV export, exclusion rules, and a command line for scheduled reports. Right-click integration for Explorer and File Labs.
Per-user installer, no UAC prompt; reading the MFT needs administrator rights, which the app asks for only when a scan needs them. No account, no telemetry. MIT licence.
Features
- Reads the NTFS Master File Table: a whole drive in seconds
- Folder tree with size bars, percentages and file counts
- File types, largest files, search by name, size or age
- Duplicate finder with the space you would get back
- Every scan stored; compare with an earlier scan
- HTML and CSV export, exclusion rules, command line