WindowsClear: moving AppData to another drive and leaving a junction behind

What it actually does, and why it is not a cleaner

WindowsClear is a disk cleanup tool for the Windows system drive, focused on reclaiming the space that AppData directories consume. Its approach is migration rather than deletion. The tool scans out the software data folders taking up large amounts of space, moves them in one action to another disk such as D drive, and automatically creates a directory junction in the original location so the software runs seamlessly as if nothing had moved. The Chinese project description gives it a name, 愚公移盘, the Foolish Old Man Who Removed the Mountains, which is the classical Chinese parable of moving a mountain by patient work, and the same description explains that it achieves a kind of C drive slimming and C drive expansion without repartitioning. So the mechanism is relocation with a redirect, and the application sees a transparent filesystem, which is why the documentation can say the software still opens after the move.

The workflow, and the deliberate suggestion to start small

The usage section is five steps and one piece of advice that matters more than the rest. You run WindowsClear.exe as administrator. You click the button to scan for large folders. You tick the applications you want to migrate in the list, and the recommendation is to start with software that is not important. You choose a target root directory, for example D:\AppData. You click to execute the migration and wait for it to finish. That third step is the one a reviewer should take seriously. The tool is a bulk file mover that runs with elevated rights and the ability to end processes, and the project's own documentation tells you to try it on something you do not care about first, which is a better safety instruction than any warning about backups.

How the scan finds the space

The smart scan feature automatically analyses %LOCALAPPDATA% and %APPDATA%, quickly locating the large occupants taking up more than 10 percent of the space, which is described as making the cleanup more efficient. The threshold is the interesting parameter, because it is what keeps the list usable. A list of every folder under AppData is useless for this purpose, since AppData contains hundreds of directories, most of them small. Filtering to the handful that account for the bulk of the usage turns the tool from a file browser into something you can act on in one pass. The scanning is done with the walkdir crate, and the caching feature means a second scan with nothing changed returns the results almost instantly, with chrono used for the cache timestamps and directories for locating the user paths.

The junction is the whole trick, and it needs administrator rights

The seamless migration feature works by creating a Junction link in the original position after moving the files across drives, so no application needs reconfiguring. The documentation is explicit about why elevation is required, that creating directory junctions with mklink /J and querying or ending other processes usually need administrator rights. That is the crux of the design and also its main risk. A junction is transparent to applications, which is the reason the tool can move a game's or a browser's data directory without breaking it, but the same transparency is what makes an incorrect move hard to diagnose later, since the application is looking at a path that is really somewhere else. The README also tells you how to reverse it, by deleting the shortcut on the C drive, the folder with the arrow icon, and cutting the files from the D drive back into their original place.

Handling files that are in use, and rolling back when something goes wrong

Two features under the safety heading cover the hard cases. The occupancy cleanup feature automatically detects files that are in use and supports automatically ending the related processes, using the Windows Restart Manager technology, and the documentation is honest that this is not a low level implementation, so not everything can be cleaned and the effect on space released is basically unaffected. The failure rollback feature says that if an error occurs during the migration, it automatically attempts to restore, protecting the data. That is the right behaviour for a tool doing bulk file operations under elevated rights, and the combination of the two, ending a process that holds a lock and restoring files if the copy fails, is what makes the operation safe enough to run on a working machine at all.

The interface, and the Rust stack underneath it

The user experience section lists the things that make the tool pleasant to run. Extreme performance, developed in Rust with multithreaded parallel scanning. Smart caching, so a second scan with no changes returns the result instantly. A visual progress bar accurate to the byte, showing real time transfer speed and an estimate of the remaining time. A Chinese and English interface with one click switching. And pause and continue, so a large transfer can be stopped mid way. The stack in the Cargo.toml explains the choices. The GUI is egui with eframe, the immediate mode interface, and rfd provides the native file dialog for choosing the target directory. Rayon and crossbeam-channel provide the parallel scanning, the windows crate carries the Win32 API calls including the Restart Manager and the file system features, filetime preserves timestamps on moved files, and uuid v4 names things. The release profile favours build speed with opt-level 2, LTO enabled, one codegen unit and symbols stripped.

What the tool will not do, and how it differs from the built-in cleanup

The frequently asked questions section is where the tool draws its line, and the distinction is important for anyone who installs it expecting it to fix a full disk. For the question of which C drive files can be deleted, the answer is that WindowsClear does not recommend deleting system files directly, and reaches its slimming through migrating AppData, and that for actual deletion the advice is to use the system's own Storage Sense and Disk Cleanup first, focusing on temporary files in %TEMP%, the recycle bin and update caches, and to avoid deleting Windows or Program Files directories. For the question of whether C drive expansion requires repartitioning, the answer is that expansion normally involves partition changes, and WindowsClear offers an alternative that does not touch partitions. The framing is a tool for one specific problem, with a clear recommendation to use the platform's own facilities first.

Building it, and where the project stands

The project is written in Rust, and the build guide is two commands. You clone the repository with git, change into the WindowsClear directory, and compile a release build with cargo build --release. The crate name in the Cargo.toml is cpan_mover, which reflects an earlier name for the tool, and the version there is 0.1.3, matching the v0.1.3 release from March 2026, with v0.1.1 in January and v0.1.2 later the same month. The licence is MIT, and the primary language is recorded as Rust. The last push to the repository was on 2026-05-12, the repository is not archived, and there is a README_EN.md alongside the Chinese one, so the project does aim to be readable outside its original audience. The distribution is a Windows executable linked from the releases page rather than a package, which is the expected shape for a tool that needs administrator rights and a native GUI.

git clone https://github.com/tanaer/WindowsClear.git
cd WindowsClear

cargo build --release

Editorial conclusion

WindowsClear suits a Windows user whose system drive is full because applications have accumulated large caches under AppData, and who wants to move them rather than delete them, so applications keep working unchanged. It is the wrong choice if the space problem is in Program Files or the Windows directory, since the documentation explicitly recommends the built-in Storage Sense and Disk Cleanup for temporary files, the recycle bin and update caches, and a poor fit for a machine you do not administer, because creating junctions and ending other processes both require administrator rights. Before you run it, read the recovery instructions, because undoing a migration means deleting the junction and moving the files back by hand, and the documentation itself suggests starting with software that does not matter much.

Frequently asked questions

Official sources

1. Issues
2. License: MIT
3. README
4. Releases
5. tanaer/WindowsClear on GitHub