Free Up Disk Space with Compact GUI

Yes, Compact GUI is safe. The project is open-source under the GPL-3.0 license, and all source code is publicly available on GitHub for anyone to inspect. The software has over 6,700 GitHub stars and more than 82,000 community-submitted compression results, which reflects a large and active user base that has been using it since 2017.

Compact GUI works by calling the built-in Windows compact.exe command-line tool through native NTFS APIs. It does not modify your files in any permanent way. The compression is transparent, meaning Windows handles the decompression automatically when you open a file. Your antivirus might briefly flag the download because the .exe is not signed with an EV code signing certificate, but this is a false positive common with independent open-source projects.

• Download only from the official GitHub Releases page at github.com/IridiumIO/CompactGUI/releases or via winget install CompactGUI
• The standalone .exe is 2.8 MB. If a download site offers a larger file or a different installer, that is not the real thing
• Check the SHA256 hash listed on the GitHub release page against your downloaded file
• The software does not require admin rights for standard compression tasks

Pro tip: If Windows SmartScreen blocks the download, click “More info” then “Run anyway.” This happens because open-source developers rarely pay for code signing certificates, not because the file is dangerous.

For a direct link to the verified download, visit our download section.

The only official source for Compact GUI is the GitHub repository maintained by IridiumIO at github.com/IridiumIO/CompactGUI/releases. The latest stable release is v3.8 (released February 24, 2025) and the latest beta is v4.0 Beta 6 (July 16, 2025).

There are several third-party sites that repackage Compact GUI downloads, and some of these bundle adware or outdated versions. MajorGeeks and Softpedia carry the genuine file, but GitHub is always the safest bet. You can also install it through Windows Package Manager by running winget install CompactGUI in a terminal, or through Chocolatey with choco install compactgui. Both package managers pull directly from the official release.

• Official GitHub: github.com/IridiumIO/CompactGUI/releases
• Winget: winget install CompactGUI
• Chocolatey: choco install compactgui

A common mistake is downloading from random “free download” sites that wrap the installer in their own executable. If the file is larger than 3 MB (the standalone exe is 2.8 MB), or if it asks you to install a toolbar or browser extension, you grabbed a fake.

Pro tip: Use the winget method if you want automatic updates later. Run winget upgrade CompactGUI anytime to pull the latest version without visiting any website.

Head to our download section for direct links and file size verification details.

Yes, Compact GUI works on both Windows 10 and Windows 11 without issues. The software uses Windows’ native NTFS compression APIs, which are part of the operating system itself and work the same on both versions.

The v3.8 stable release runs on .NET 6 runtime. The v4.0 beta requires .NET 9, which Windows 11 users can install from Microsoft’s website or through winget. The software has been tested across Windows 11 22H2, 23H2, and 24H2 by thousands of users. On the GitHub issues page, only a handful of reports mention Windows 11-specific problems, and most of those relate to the beta branch rather than stable.

There is one important exception for Windows 11 users: games that use DirectStorage should not be compressed with Compact GUI. DirectStorage bypasses the normal file I/O pipeline to load assets directly from NVMe SSDs into GPU memory. Compressing these files would force them through the regular decompression path, which defeats the purpose of DirectStorage and could cause stuttering or crashes. Games using DirectStorage include Forspoken, Ratchet & Clank: Rift Apart, and a growing list of newer AAA titles.

• Windows 11 (all editions, 22H2 and later): fully supported
• DirectStorage games: do not compress these folders
• .NET 6 runtime required for v3.8 stable; .NET 9 for v4.0 beta

Pro tip: If you are unsure whether a game uses DirectStorage, check the game’s Steam store page under system requirements, or search for the game name in the Compact GUI community database. Games with DirectStorage support are typically flagged there.

Check our system requirements section for full hardware and software specs.

Compact GUI has minimal system requirements. You need Windows 10 or later, an NTFS-formatted drive, and .NET 6 runtime (for v3.8) or .NET 9 (for the v4.0 beta). That covers it for the basics.

The application itself uses very little memory and CPU. The standalone executable is just 2.8 MB, and the self-contained “mono” build that bundles its own .NET runtime is about 72 MB. During active compression, CPU usage rises depending on the algorithm you pick. XPRESS4K and XPRESS8K are lightweight and finish quickly. LZX uses more CPU and takes longer, but it produces smaller files. On a modern quad-core processor, compressing a 50 GB game folder with XPRESS8K takes roughly 10-20 minutes.

The software works on NTFS drives only. If your game drive is formatted as exFAT, FAT32, or ReFS, Compact GUI will not work on those partitions. Most internal SSDs and hard drives in Windows installations use NTFS by default, but external drives and USB sticks are often formatted differently.

• OS: Windows 10 or Windows 11 (64-bit)
• Runtime: .NET 6 (v3.x) or .NET 9 (v4.x beta)
• File system: NTFS only (not FAT32, exFAT, or ReFS)
• Disk space: 3 MB for standalone, 72 MB for self-contained build
• Admin rights: Not required for most operations

Pro tip: To check your drive’s file system, open File Explorer, right-click the drive, select Properties, and look for “File system: NTFS” on the General tab.

See the full system requirements table for minimum and recommended specs.

No, Compact GUI is a Windows-only application. It relies on Windows’ built-in NTFS compression feature (compact.exe), which is part of the Windows operating system kernel. NTFS compression does not exist on macOS or Linux.

macOS uses APFS, which has its own transparent compression, but Apple does not expose a user-facing tool for it. Linux supports Btrfs transparent compression with zstd or lzo algorithms, but that requires a different set of tools entirely (like compsize and mount options). Neither of these platforms can run Compact GUI, even through compatibility layers like Wine, because the program needs direct access to Windows NTFS API calls.

If you are on a Linux system with an NTFS partition (for example, a dual-boot setup), you could technically mount that partition and run the Windows command-line tool from within Windows. But there is no way to use Compact GUI from the Linux side.

• Windows 10/11: fully supported
• macOS: not compatible (no NTFS compression support)
• Linux: not compatible (uses different file systems)

Pro tip: If you are on Linux and want similar transparent compression for games, look into Btrfs with zstd compression. Mount your game partition with compress=zstd:3 for comparable space savings with minimal CPU overhead.

For the Windows download, see our download section.

Yes, Compact GUI is 100% free and open-source. There is no paid version, no premium tier, no ads, and no data collection. The project is licensed under GPL-3.0, which means anyone can use, modify, and distribute it freely.

The developer, IridiumIO, maintains the project on GitHub as a personal open-source effort. There is no company behind it and no monetization. The community compression database, which contains over 82,000 submissions across 9,779+ tested games, is also freely accessible. Every feature in Compact GUI is available to all users without restrictions.

This is worth highlighting because a paid competitor called SNUG appeared on Steam in 2024. SNUG does the same basic thing (transparent NTFS compression) but charges money for it and has mixed reviews (around 65% positive on Steam). Compact GUI provides the same underlying compression technology at no cost, with a larger community database and more active development.

• Price: free, forever
• License: GPL-3.0 open-source
• No ads, no tracking, no premium upsells
• All features unlocked for every user

Pro tip: If you find Compact GUI useful, consider starring the GitHub repository or submitting your compression results to the community database. That helps the project grow and improves compression estimates for other users.

Learn more about what you get in our features section.

Compact GUI is free and open-source. SNUG is a paid application on Steam that does the same basic job. Both tools use Windows’ built-in NTFS transparent compression, so the actual compression technology is identical.

The main differences come down to the interface, automation features, and community support. Compact GUI has been around since 2017, has 6,700+ GitHub stars, and includes a community database of 9,779+ tested games with 82,000+ compression results. Its Background Watcher feature automatically recompresses game folders after updates. SNUG offers a one-click project compression feature and auto-detection of installed games, but carries mixed reviews on Steam (around 65% positive) and has a much smaller user base.

• Compact GUI: Free, 6,700+ stars, 9,779 games in database, 4 compression algorithms, background watcher, Explorer context menu, active development (v4.0 beta)
• SNUG: Paid (Steam), auto-imports games, one-click project compression, smaller community, mixed reviews
• Compactor: Free, Rust-based, faster pre-compression checks, but development stopped in 2020

For most users, Compact GUI is the better choice. It has more features, a larger database for estimating compression ratios, and you pay nothing for it. SNUG might appeal to someone who wants a more polished “set and forget” experience and does not mind paying, but the underlying compression is the same Windows API.

Pro tip: Before compressing a large game, search its name in the Compact GUI community database to see the average compression ratio reported by other users. This saves you time by showing whether compression is worthwhile for that specific game.

See our features overview for a breakdown of what Compact GUI offers.

Compact GUI does not have a traditional installer. The standard download is a standalone portable .exe that you run directly. No installation wizard, no registry entries, no Start Menu clutter.

The v3.8 stable release requires .NET 6 Desktop Runtime. If you do not have it installed, Windows will prompt you to download it on first launch. The v4.0 beta needs .NET 9 instead. The self-contained “mono” build (72 MB) bundles the .NET runtime so you can skip that step entirely, but it is a larger download.

1. Go to the download section on this page or visit GitHub Releases
2. Download CompactGUI.exe (2.8 MB standalone) or CompactGUI-mono.exe (72 MB self-contained)
3. If Windows SmartScreen shows a warning, click “More info” then “Run anyway”
4. If prompted, install .NET 6 Desktop Runtime from the Microsoft link that appears
5. Run CompactGUI.exe. The main window opens immediately with a search bar and folder selector

You can also install via command line: open a terminal and run winget install CompactGUI or choco install compactgui. Both pull the official release automatically.

Pro tip: Place the .exe in a folder like C:ToolsCompactGUI and add that folder to your system PATH. This lets you right-click any folder in Explorer and open it with Compact GUI if you enable the context menu integration from the app’s settings.

For a full walkthrough, see our Getting Started guide.

Choose the portable standalone .exe in almost every case. Compact GUI does not offer a traditional installer. Both available downloads are portable: the regular CompactGUI.exe (2.8 MB, needs .NET runtime installed separately) and the self-contained CompactGUI-mono.exe (72 MB, bundles its own .NET runtime).

The regular standalone build is what most people use. It is tiny, launches instantly, and keeps its config data in the same folder where you place the .exe. The self-contained mono build exists for situations where you cannot or do not want to install the .NET 6 Desktop Runtime system-wide. This is useful on locked-down work computers or if you want to run it from a USB drive.

• CompactGUI.exe (2.8 MB): Best for most users. Requires .NET 6 runtime installed. Tiny download, fast launch.
• CompactGUI-mono.exe (72 MB): Best for USB drives or restricted PCs. Self-contained, no dependencies. Larger file size.

Since both are portable, uninstalling means deleting the .exe file and its config folder. No registry cleanup needed, no leftover files scattered across your system.

Pro tip: If you already have .NET 6 installed (many apps require it), grab the 2.8 MB version. Run dotnet --list-runtimes in a terminal to check which .NET versions you have.

Download either version from our download section.

Most crashes and startup failures trace back to corrupted config files or missing .NET runtime components. The fix is straightforward in most cases.

Compact GUI stores its configuration in an AppData folder. When this data gets corrupted (often after a Windows update or a forced shutdown during compression), the app can hang on launch or crash immediately. GitHub issue #592 and #401 both document this pattern. The v4.0 beta has also had stability issues that the developer is actively fixing, so if you are on the beta branch, switching to the v3.8 stable release often resolves the problem.

1. Close Compact GUI completely (check Task Manager for any lingering processes)
2. Navigate to %APPDATA%CompactGUI and delete or rename the folder
3. Relaunch the application. It will recreate fresh config files on startup
4. If it still crashes, verify your .NET runtime: run dotnet --list-runtimes in a terminal and confirm .NET 6 (for v3.8) or .NET 9 (for v4.0 beta) is listed
5. As a last resort, download the self-contained mono build (72 MB) which bundles its own .NET runtime

Users on software RAID volumes or using disk caching tools like PrimoCache have reported hangs during compression (GitHub issue #489). If you are in that situation, try compressing a folder on a standard NTFS drive first to confirm the app works, then investigate the RAID/cache interaction.

Pro tip: The v4.0 beta has known UI freezing issues that appear in the GitHub issue tracker. For production use, stick with v3.8 stable until v4.0 reaches a full release.

For installation help, check our Getting Started guide.

For most games on modern hardware, Compact GUI has zero measurable impact on FPS or load times. On HDDs specifically, loading times can actually decrease because the compressed files are physically smaller on disk, meaning the drive head reads less data.

The compression is handled by a Windows kernel driver that decompresses files on the fly as they are read. On any CPU made in the last decade, this decompression adds less than 1% CPU overhead. Multiple Reddit threads on r/pcgaming and r/pcmasterrace confirm this, with users reporting no FPS difference after compressing their entire Steam libraries.

There are two exceptions where performance might be affected:

• DirectStorage games on Windows 11: These games load assets directly from NVMe SSDs to GPU memory, bypassing normal file I/O. Compression forces these files through the standard decompression pipeline, adding latency. Do not compress DirectStorage-enabled games.
• Low-power handheld PCs: Devices like the Steam Deck (running Windows), MSI Claw, or Asus ROG Ally have weaker CPUs. Some users on r/MSIClaw report slightly longer load times with LZX compression on CPU-constrained devices. Use XPRESS4K or XPRESS8K instead of LZX on handhelds.

The XPRESS algorithms (4K, 8K, 16K) are faster to decompress than LZX. XPRESS8K hits the best balance between compression ratio and speed for gaming. LZX produces smaller files but takes longer to decompress and compress.

Pro tip: Compress one game first, launch it, play for 30 minutes, and check for stuttering. If everything runs fine, compress the rest of your library. You can always uncompress from within Compact GUI if something goes wrong.

Read about all compression algorithms in our features section.

Windows updates occasionally break .NET runtime installations or reset file associations, which can cause Compact GUI to stop launching. This is not a bug in Compact GUI itself, but a side effect of how Windows handles runtime updates.

The most common scenario is a major Windows feature update (like moving from 23H2 to 24H2) that upgrades or removes the .NET 6 runtime. When this happens, the standalone CompactGUI.exe cannot find its required runtime and either shows an error dialog or silently fails to open.

1. Open a terminal and run dotnet --list-runtimes to verify .NET Desktop Runtime 6.x is still installed
2. If .NET 6 is missing, reinstall it from Microsoft’s .NET 6 download page
3. If the runtime is present but Compact GUI still fails, delete the %APPDATA%CompactGUI folder and try again
4. Download the latest v3.8 release from GitHub in case your local copy is outdated

Another post-update issue is that Windows sometimes resets NTFS compression attributes on system folders. Compact GUI’s Background Watcher feature helps with this by automatically recompressing game folders after they are updated by Steam, Epic, or other launchers.

Pro tip: Switch to the self-contained mono build (72 MB) if you are tired of .NET runtime issues. It bundles everything it needs and is immune to Windows removing or upgrading shared .NET runtimes.

See our download section for both the standalone and self-contained builds.

Compact GUI does not include a built-in auto-updater. To update, download the latest release from GitHub and replace the old .exe file with the new one. Your compression history and settings are stored separately in %APPDATA%CompactGUI, so they persist between versions.

The fastest update method depends on how you originally installed it:

1. Manual download: Visit GitHub Releases, download the latest CompactGUI.exe, and replace the old file in your installation folder
2. Winget: Run winget upgrade CompactGUI in a terminal. This checks for newer versions and updates automatically
3. Chocolatey: Run choco upgrade compactgui

The current stable release is v3.8 (February 2025). The v4.0 beta series is available for early adopters who want the newest features, but expect occasional bugs. If you are on the beta track, check GitHub more frequently as beta releases come out every few weeks.

Pro tip: Star or watch the GitHub repository to get email notifications when new releases drop. Click the “Watch” button at the top of the repo page and select “Releases only” to avoid notification spam from issue discussions.

Grab the latest version from our download section.

The latest stable version is v3.8, released on February 24, 2025. The latest beta is v4.0 Beta 6, released on July 16, 2025. The v4.0 line is a major rewrite with a redesigned interface and new features.

Version 3.8 is the recommended release for daily use. It includes the Background Watcher service for automatic recompression, Windows Explorer context menu integration, drag-and-drop folder support, and access to the community compression database with 9,779+ tested games. It runs on .NET 6 and has been the default stable build for months.

The v4.0 beta series brings a modernized UI built on .NET 9, improved compression speed, better handling of large folders, and new file type exclusion filters. However, multiple GitHub issues show that the beta still has stability problems, including UI freezes when analyzing very large directories and occasional crashes during compression.

• v3.8 stable: Reliable, well-tested, .NET 6, all core features working
• v4.0 Beta 6: Redesigned UI, .NET 9, faster compression, but has known bugs

Pro tip: You can run v3.8 and v4.0 beta side by side in different folders since both are portable executables. Test the beta on non-critical folders while keeping the stable version for your main game library.

Check our features section for details on what each version offers.

Compact GUI is the better choice for most users in 2025. Both tools use the same Windows NTFS compression technology, so the actual compression ratios are identical. The difference is in the interface, features, and maintenance status.

Compactor (by Freaky on GitHub) is a Rust-based GUI that has not received an update since 2020. It has 1,300 GitHub stars and was known for its “compresstimation” feature that pre-checks how compressible files are before starting. It also has a faster skip mechanism for already-compressed data. However, with 5+ years of no updates, it does not support newer Windows 11 features, and bug reports go unanswered.

Compact GUI has 6,700+ stars, active development (v4.0 beta released July 2025), a community database with 9,779+ games and 82,000+ compression submissions, a Background Watcher that recompresses after game updates, and Windows Explorer context menu integration. It handles everything Compactor does, plus more.

• Compact GUI: Actively maintained, 6,700+ stars, community database, background watcher, Explorer integration, .NET 6/.NET 9
• Compactor: Abandoned since 2020, 1,300 stars, pre-compression estimation, Rust-based, fast skip for incompressible files

Some users on r/pcgaming still prefer Compactor for its simpler, more minimal interface. GitHub issue #91 on the Compactor repo includes a user who said “I would prefer to use Compactor because CompactGUI is fairly weird with the UI.” That said, Compact GUI’s interface in v4.0 has been completely redesigned, and the community size makes it a safer long-term bet.

Pro tip: If you just want to compress one folder and never think about it again, both tools work equally well. But if you regularly install and update games, Compact GUI’s Background Watcher saves you from manually recompressing after every game patch.

See our full feature comparison for more details.

XPRESS8K is the best all-around choice for most users. It provides a strong balance between compression ratio and speed, with negligible decompression overhead on any modern CPU.

Compact GUI offers four NTFS compression algorithms, all built into Windows: XPRESS4K, XPRESS8K, XPRESS16K, and LZX. The number after XPRESS refers to the block size used for compression. Larger blocks generally mean better compression ratios but slightly slower decompression. Here is how they compare in practice:

• XPRESS4K: Fastest compression and decompression. Lowest ratio (typically 10-25% savings). Best for SSDs where speed matters more than space.
• XPRESS8K: Good balance. 20-40% savings on most games. Recommended default for gaming PCs and handhelds.
• XPRESS16K: Better ratio than 8K, slightly slower. 25-50% savings. Good for HDDs where read speed is the bottleneck.
• LZX: Highest ratio (30-60% savings) but noticeably slower compression. Decompression is still fast. Best for archival or games you rarely play but want to keep installed.

For gaming on NVMe SSDs, XPRESS8K is the standard recommendation. On HDDs, XPRESS16K or LZX can actually improve load times because the smaller files mean less physical data for the drive to read. On handheld PCs with weaker CPUs (Steam Deck in Windows mode, MSI Claw), stay with XPRESS4K or XPRESS8K to avoid any decompression overhead during gameplay.

Pro tip: You can test different algorithms on the same folder. Compress with XPRESS8K first, note the final size, then uncompress and try LZX. The community database on GitHub also shows which algorithm most users picked for each game, which gives you a quick recommendation.

Learn more about each algorithm in our features section.

Space savings vary by game, but typical results range from 20% to 60%. The community database shows an average of around 40% across 9,779+ tested games and 82,000+ submissions. That means a 100 GB game folder typically shrinks to 40-60 GB.

The savings depend on what kind of data the game stores. Pre-compressed assets like .ogg audio, .mp4 video, and JPEG textures barely compress at all. Uncompressed textures, XML configuration files, and raw audio files compress very well. Games with lots of pre-rendered cutscenes save less space than games built on text-heavy engines with uncompressed assets.

Real-world examples from the community database and Reddit threads:

• Cyberpunk 2077 (61.3 GB): compresses to roughly 34.8 GB with XPRESS8K (43% savings)
• ARK: Survival Evolved (400+ GB): up to 50% savings, one of the most popular use cases on Reddit
• Aethermancer (5 GB): compressed to 900 MB (82% savings, reported on r/MSIClaw)
• Stellaris: 40-50% savings reported on r/pcgaming

Some games show minimal savings (under 10%). This usually means the game files are already heavily compressed by the developer. If the community database shows a low compression ratio for a specific game, compressing it is not worth the time.

Pro tip: Before compressing your whole library, use the Compact GUI search bar to check each game against the community database. Focus on the games with 30%+ estimated savings first. A library of 20 games at 40% average savings can easily free up 200-400 GB.

See our download section to get started.

Uncompressing is built into Compact GUI and takes one click. Open the application, select or drag in the folder you want to decompress, and click the “Uncompress” button. The files return to their original uncompressed state with no data loss.

NTFS transparent compression is fully reversible. The compression metadata is stored in the NTFS file system itself, not in the files. When you uncompress, Windows simply removes the compression attribute and writes the full uncompressed data back to disk. Your game or application will not notice any difference, because it already reads the files as if they were uncompressed (that is what “transparent” means).

1. Open Compact GUI
2. Select the compressed folder (drag-and-drop or browse)
3. The interface shows the current compressed size and a “Compressed” status
4. Click the “Uncompress” button
5. Wait for the process to finish. Larger folders take a few minutes

You can also uncompress from the command line using Windows’ built-in tool: compact /u /s:"C:GamesYourGame". This does the same thing without needing Compact GUI open.

Pro tip: If a game starts acting strangely after compression (rare, but possible with DirectStorage games or certain anti-cheat systems), uncompress it immediately. The process takes roughly the same time as the original compression and restores everything exactly.

For more details on using the software, visit our Getting Started guide.

Point Compact GUI at your Steam game’s installation folder and click compress. Steam does not interfere with NTFS compression, and the game continues to work normally through Steam’s launcher.

Steam games are typically installed in C:Program Files (x86)Steamsteamappscommon or wherever you set your Steam library folder. Each game has its own subfolder. You compress individual game folders, not the entire Steam directory.

1. Open Compact GUI
2. Navigate to your Steam library folder or drag the specific game folder into the window
3. Use the search bar to find the game by name. If it is in the community database, you will see estimated compression ratios from other users
4. Select your compression algorithm (XPRESS8K is the recommended default)
5. Click “Compress” and wait for it to finish
6. Launch the game through Steam as usual. It runs the same way

One thing to watch: Steam game updates will uncompress the updated files. If a game gets a 5 GB patch, those new files arrive uncompressed. Compact GUI’s Background Watcher feature automatically detects this and recompresses updated folders. Enable it from the application settings so you do not have to manually recompress after every patch.

Do not compress your entire steamapps folder at once. Compress individual game folders instead. This gives you control over which games stay compressed and makes it easier to uncompress a single game if needed.

Pro tip: Sort your Steam library by install size (Library > Storage Manager) and start compressing the biggest games first. Compressing your top 5 largest games often frees up more space than compressing 20 smaller ones.

Learn more in our Getting Started guide.