Where the installer should come from
TreeSize is developed by JAM Software, and the developer's own site (jam-software.com) is the source that can actually confirm you're getting the current, unmodified build. If you'd rather use a source you already trust, that's a reasonable choice too — the point is to avoid random file-hosting sites that bundle installers with browser toolbars or other unrelated software.
We don't control or inspect any installer file, so we can't tell you that a specific download is safe. Treat any setup file the way you'd treat any other executable: verify it yourself before running it.
Decide on the edition before you download anything
Free and Professional are separate products with separate installers, so it's worth deciding which one you need before you go looking. If you're a home user checking why C:\ is full, the free edition covers that. If you need scheduled scans, duplicate detection, or reporting across a network share, you're looking at a paid edition and should start from the Professional page.
The free vs. Professional comparison lays out the practical differences so you're not guessing halfway through setup.
Installer build vs. a portable build
TreeSize is generally offered both as a conventional installer, which writes to Program Files and the registry, and as a portable build that can run from a USB stick or a folder without a formal install step. Portable is useful on a machine where you can't or don't want to install software, such as a client's PC during a one-off cleanup visit.
The two builds behave differently around settings storage and the Explorer context-menu entry, which the portable version generally can't register the same way. We cover the trade-offs in TreeSize Portable explained.
What to check before you run the setup file
Before opening any downloaded .exe, a few minutes of checking saves a lot of regret later.
- Check the publisher on the file's properties Right-click the downloaded file, choose Properties, and look at the Digital Signatures tab. A missing or unrelated publisher name is a reason to stop and re-download from a different source.
- Confirm the source URL Look at the actual domain you downloaded from, not just the page title. Search-engine ads and copycat sites frequently mimic a developer's branding.
- Scan the file before running it Run it through your existing antivirus or Windows Defender, or upload it to a multi-engine scanning service, especially if it came from anywhere other than the developer's own site.
- Read every setup screen Installers for free software sometimes include optional offers for unrelated toolbars or trial software. Uncheck anything you don't recognize instead of clicking through on autopilot.
For a broader look at how to judge whether a copy of TreeSize is trustworthy, see is TreeSize safe?
What installation generally looks like
Exact screens vary by version, but a typical Windows installer for TreeSize follows the pattern of most desktop software: accept a license agreement, choose an install folder, decide whether to add the Explorer context-menu entry and a desktop shortcut, then let the installer copy files and finish.
Once it's done, the first real step is running an actual scan — our how-to-use walkthrough picks up from there.
32-bit, 64-bit, and Windows version compatibility
Modern Windows PCs are overwhelmingly 64-bit, and current software builds are generally aimed at that architecture; a 32-bit build may still be offered for older machines. Which builds are available, and which Windows versions they support, is something only the developer's own release notes or system-requirements page can confirm accurately at any given time.
If you're specifically on Windows 11 or Windows 10 and want version-specific notes rather than general compatibility language, see our Windows 11 and Windows 10 pages.
Questions about downloading TreeSize
Can I download TreeSize directly from this site?
No. We don't host installers. This page explains how to evaluate and obtain the file elsewhere, primarily from the developer's own site.
Is a download from a third-party software site safe?
Why does the installer ask to add a context-menu entry?
Do I need administrator rights to install it?
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Last reviewed by the jam-software.org editorial team on . Spotted something out of date? Tell us.