The limitation should not affect too many users, though.

TreeSize Free 4.5 is the last version that supports 32-bit operating systems. Windows users who run the operating system on a 32-bit only device can't run or upgrade to the new TreeSize version. Existing users may select Help > Check for Updates to run a check for updates from within the application. Options to install the free version or extract it to run it as a portable copy are provided.

They push the professional version, but you get the free version download eventually.

The new version can be downloaded from the developer website. TreeSize Free 4.6 is the first release of the free version since November 2021. While I switched to the excellent WizTree years ago, TreeSize Free has always been on the radar ever since the first review of TreeSize back in 2010 here on this site.