Is this different or more or less useful than WinDirStat? I've been using WinDirStat for a long time since it's free to find large files and figure out what I need to uninstall or delete, and it is a great program. I'll give this a try and see how it compares.

When in the user interface there is a check box on every node in the tree including drive letters but perversly when one attempts to select a drives check box it pops up a refusal alert box! stating:

"This software uses the checked resource(s) for Deleting, Moving and Copying operations in batch mode, but these actions are not available for a drive. So, you cannot check a drive."

Well duh if we cannot select a drive DON'T enable and show the check box on a drive letter!!!!

Point of fact if select boxes are enabled in windows we CAN select whole drives and we can copy entire drive to clipboard for copying entire drives or renaming a volume... I noted that when I cut a moderate sized folder with 20G or so of large WAV files via this program to windows explorer window onto a seperate physical drive the move operation was about a third of the speed of the same operation done from two windows explorer windows and the program kept announcing it had become unresponsive periodically as the move operation apeared to be a blocking operation rather than an independant thread. It did manage to eventually copy the files accross but did not complete the move operations deleting of the source files and had to re-do the operation between two windows explorer windows (that's how I saw the speed comparison between this programs move and windows explorers native move operation.)

It was also very laborious to populate the tree having to select each folder to expand the tree branch for each and every sub folder... with the Comuting resources operation on each selection being completely blocking making the program unresponsive as it enumerates selected resources.

The joke is this is called 1Tree Pro but each drive letter is a seperate tree.... there is not a single tree rooted at the This Computer/My Computer node that can be enumerated in one go... Each child branch has to be enumerated and expanded one by one... really time consuming it requiring so much user attention in between each branches enumerations... would be more helpful if one could set it to enumerate all local and mapped network drive letter file systems in one go and let the user go and do something else while the program churns through the file systems and not require end user sitting waiting around to instigate the next folders enumeration.

It works fine but maybe the slowest Tree utility I have ever tried.

I just wanted to say thank you for including the very clear specifics of the license being given away. Thank you!

Uninstalled after waiting for a return from it's "Processing" screen for several minutes. I could care less if it works when it takes so long to get results.

Yes, I do work at a large company IT Help Desk.
We use Tree Size Free to view disk usage of our large NAS storage (60TB) drives.
We have also used WinDirStat (which is also free) as mentioned by another commenter.
I also have used them on my workstation (Windows 10).
Both work very well.

Well, it works, but "Computing resources size, please wait..." and wait... and wait... - and I have quick computer with SSD. And it reads resources again and again during use, every time I open a directory which was not opened yet in this session - it renders this sw almost unusable. I shall keep it for a while, maybe by next great disk cleaning it will be useful, I will see... Really obsolete GUI look and feel is a bit surprising (what about skins?). On the other hand this sw does what it promises. Just too slowly for me - even starting it takes a few minutes (every time). I dont see much of advantage compared tu Windows File Explorer :-(- OK, I see file/directory size at once and for all elements in the tree, but I have to wait too long for it.

The FASTEST free alternative that I have found over the years, is https://wiztree.en.lo4d.com/windows.

There is not a visual represantation which I kind of expected. It only shows the directory list and their sizes, something which any file management software would do anyway without the 2 - 3 seconds loading time.

Same message as yesterday: A required privilege is not held by the client.

It seems to work, takes a while to load resources, I have a 1 Tb hard drive and took a few mins, but works as expected.

This sort of makes me think of a free (or paid) offering called TreeSize which looks similar and likely works as good, maybe better.

The icons used in this program make me think this was designed for Windows XP. Vista at the latest.

For this purpose I use the excellent -- and FREE -- WinDirStat, available at: www.windirstat.net
The benefit of this is that if/when I change to a new computer, I don't lose the software for which the licence is no longer any good.