Browse free open source System software and projects for Windows below. Use the toggles on the left to filter open source System software by OS, license, language, programming language, and project status.

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  • 1
    WinMerge

    WinMerge

    Windows visual diff and merge for files and directories

    WinMerge is a Windows tool for visual difference display and merging, for both files and directories. It is highly useful for determining what has changed between file versions, and then merging those changes. WinMerge has Unicode support, Flexible syntax coloring editor, Visual SourceSafe integration, and Windows Shell integration. Regexp filtering for filenames and lines. Side-by-side line difference and highlights differences inside lines. A file map shows the overall file differences in a location pane. The user interface is translated into several languages.
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    Downloads: 32,238 This Week
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  • 2
    NSIS: Nullsoft Scriptable Install System

    NSIS: Nullsoft Scriptable Install System

    Windows installer development tool

    NSIS (Nullsoft Scriptable Install System) is a professional open source system to create Windows installers. It is designed to be as small and flexible as possible and is therefore very suitable for internet distribution. Being a user's first experience with your product, a stable and reliable installer is an important component of succesful software. With NSIS you can create such installers that are capable of doing everything that is needed to setup your software. NSIS is script-based and allows you to create the logic to handle even the most complex installation tasks. Many plug-ins and scripts are already available: you can create web installers, communicate with Windows and other software components, install or update shared components and more.
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    Downloads: 11,912 This Week
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  • 3
    Bulk Crap Uninstaller

    Bulk Crap Uninstaller

    Remove large amounts of unwanted applications quickly.

    Bulk Crap Uninstaller (in short BCUninstaller or BCU) is a free (as in speech and beer) bulk program uninstaller with advanced automation. It excels at removing large amounts of applications with minimal to no user input, while requiring next to no technical knowledge. It can detect most applications and games (even portable or not registered), clean up leftovers, force uninstall, automatically uninstall according to premade lists, and much more. Bulk Crap Uninstaller is licensed under Apache 2.0 open source license, and can be used in both private and commercial settings for free and with no obligations, as long as no conditions of the license are broken.
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    Downloads: 8,804 This Week
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  • 4
    Rufus

    Rufus

    Utility to create bootable USB flash drives

    Rufus is a standalone app designed to format and create a bootable USB drive for a large variety of ISOs. The app is just over 1MB in size and is notably faster than similar competitor apps such as the Windows 7 USB utility, Universal USB Installer, and UNetbootin. Rufus can come in handy when you need to simply format a USB drive, install an OS on a machine that lacks a CD/DVD-ROM drive, or when you need to boot an operating system temporarily without intentions of actually installing the media. This can be immensely useful while you're on the go or just need access to an OS for a temporary, isolated reason. The app can even be used to flash firmware to BIOS or other destinations by just using DOS. Even though Rufus is a tiny utility in comparison to other USB creation tools that can be rather bulky in size, it contends easily with the competition and creates bootable USB drives in record time!
    Downloads: 1,169 This Week
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  • 5
    BleachBit

    BleachBit

    deletes junk files to free disk space and improve privacy

    BleachBit frees disk space and maintains privacy. Cleans cache, Internet history, temporary files, logs, cookies, Firefox, Google Chrome, Flash, Windows, Linux, and more. Downloads are at www.bleachbit.org and source code is at GitHub.
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    Downloads: 1,941 This Week
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  • 6
    WinDirStat: Windows Directory Statistics

    WinDirStat: Windows Directory Statistics

    A disk usage statistics viewer and cleanup tool for Windows

    WinDirStat (Windows Directory Statistics) is a disk usage statistics viewer and cleanup tool for Windows. On start up, WinDirStat reads the whole directory tree once and then presents it in three useful views. The official download location and collaboration platform for WinDirStat has moved to GitHub: https://github.com/windirstat/windirstat Downloads and source code provided on SourceForge may not always be up to date. They are primarily used for disaster recovery purposes.
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    Downloads: 1,740 This Week
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  • 7
    DropIt

    DropIt

    A flexible tool to automate processing & organizing files and folders.

    When you need to organize files, DropIt can eliminate much of the drudgery of searching and manually opening folders and moving files around. Drop a group of different files and folders on the floating DropIt image and it sorts them to defined destination folders, compresses or extracts them, opens them with associated programs or performs other defined actions. You can define how filter your files (by name, directory, size, date, properties, content or regular expressions) and associate one of the 21 available actions to perform (Move, Copy, Compress, Extract, Rename, Delete, Split, Join, Encrypt, Decrypt, Open With, Print, Upload, Send by Mail, Create Gallery, Create List, Create Playlist, Create Shortcut, Copy to Clipboard, Change Properties and Ignore). You can also organize your associations in profiles and automatically scan monitored folders at a defined time interval.
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    Downloads: 1,775 This Week
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  • 8
    PeaZip

    PeaZip

    Free Zip software and Rar extractor

    PeaZip is a free archiver tool. The application provides an unified, natively portable, cross-platform file manager and archive manager GUI for many Open Source technologies like 7-Zip, FreeArc, PAQ, UPX. Create: 7Z, ARC, Brotl, BZip, GZip, PEA, TAR, WIM, XZ, ZPAQ, ZIP, Zstandard files and more Open and extract 200+ file types: ACE, CAB, DEB, ISO, RAR, ZIPX and more Features of PeaZip includes extract, create and convert multiple archives at once, create self-extracting archives (sfx), split files, strong encryption with two factor authentication, encrypted password manager, secure deletion, find duplicate files, calculate hashes, export task definition as command line script.
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    Downloads: 1,226 This Week
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  • 9
    UltraDefrag

    UltraDefrag

    Increase your system performance with this easy to use tool

    Please note, here you can find the latest open source release of UltraDefrag (7.1.4). The most recent UltraDefrag release (15.0.0) can be found on our official website: https://ultradefrag.net UltraDefrag is a disk defragmenter for Windows, which supports defragmentation of locked system files by running during the boot process. It is easy to use without any complicated scripting or a huge load of configuration settings. You can filter the files processed by size, number of fragments, file name and path. You can terminate the process early by specifying an execution time limit.
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    Downloads: 1,250 This Week
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  • 10
    Super Grub2 Disk

    Super Grub2 Disk

    Boots into many systems and GRUB2 ones!

    Super GRUB2 Disk helps you to boot into most any Operating System (OS) even if you cannot boot into it by normal means.
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    Downloads: 1,729 This Week
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  • 11
    HotkeyP
    Keyboard/mouse/WinLIRC/joystick shortcuts for exe files, documents, folders, www pages and commands: shutdown, hibernate, desktop resolution, volume, process priority, eject CD, wallpaper, always on top, hide active window, kill process, paste text,
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    Downloads: 831 This Week
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  • 12
    D-Fend Reloaded

    D-Fend Reloaded

    A graphical environment for DOSBox

    D-Fend Reloaded is a graphical environment for DOSBox. D-Fend Reloaded is a successor of the discontinued D-Fend. Both environments look alike and D-Fend Reloaded contains all features of D-Fend. Even the D-Fend config files can be used.
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    Downloads: 705 This Week
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  • 13
    OpenEMR
    OpenEMR is an open source medical practice management application (EHR EMR PMS) featuring fully integrated electronic health records, scheduling, electronic billing, internationalization, free support, a vibrant community, and a whole lot more.
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    Downloads: 681 This Week
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  • 14
    winPenPack

    winPenPack

    The portable software collection

    winPenPack is a project that aims at collecting the most frequently used and most popular open source applications made portable, so that they can be executed without installation from any USB Flash Drive or Hard Disk. The winPenPack suites offer a wide range of portable applications like office tools, internet tools, multimedia tools, development tools, security applications and other frequently used utilities. Everything you need, completely free, open source and portable!
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    Downloads: 522 This Week
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  • 15
    uGet - Download Manager
    uGet, the Best Download Manager for Linux. uGet is a lightweight yet powerful Open Source download manager for GNU/Linux developed with GTK+, which also comes packaged as a portable Windows app. - Quick Links - Features: https://ugetdm.com/features Screenshots: https://ugetdm.com/screenshots Blog: https://ugetdm.com/blog Support: https://ugetdm.com/qa Frequently Asked Questions (FAQs): https://ugetdm.com/qa/faq RSS Feed: https://ugetdm.com/rss GitHub: https://github.com/ugetdm
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    Downloads: 497 This Week
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  • 16
    cdrtfe

    cdrtfe

    Burn optical discs in various formats

    cdrtfe is a CD/DVD/BD burning application for Microsoft Windows. You can burn data discs, Audio CDs, XCDs, (S)VCDs and DVD-Video discs. It supports creation and writing of ISO images and bootable discs. cdrtfe has a multi-language interface and is also available as portable version.
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    Downloads: 566 This Week
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  • 17
    USB Oblivion

    USB Oblivion

    Erase all traces of (broken) USB drives from Windows registry

    This utility designed to erase all traces of (broken) connected USB devices - flash-drives, disks and CD-ROMs from computer registry of Windows XP, Windows 2003, Windows Vista, Windows 7, Windows 8, Windows 10 (32/64-bit versions). The utility has a test mode of operation, i.e. without actually removing data from the registry, and, just in case, creates a .reg-file to undo any changes. There is also a fully automatic mode.
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    Downloads: 763 This Week
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  • 18
    Data Crow

    Data Crow

    The ultimate cataloguer

    Data Crow allows you to use the standard movie & video (divx, xvid, DVD, Blu-ray, etc), book (and eBooks), images, board games, comic books, games & software, music (mp3 and other music files) cataloguing modules. Besides these modules, which you can change to fit your requirements, you can create new modules (want to catalogue your stamps, equipment, or anything else?). The GUI is skinnable. Reporting (using JasperReports and their community edition JasperSoft Developer Studio ), loan administration, item importing & exporting, backup & restore and many other optional features are waiting for you.
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    Downloads: 295 This Week
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  • 19
    Snappy Driver Installer
    Snappy Driver Installer is an application for installing/updating drivers on PCs running Microsoft Windows using driverpacks or included folders with drivers. It can be used to install drivers on newly assembled PCs at places where Internet isn't available. Users can also use the software to keep their drivers up to date.
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    Downloads: 303 This Week
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  • 20
    Clover EFI bootloader

    Clover EFI bootloader

    Boot macOS, Windows, and Linux on Mac or PC with UEFI or BIOS firmware

    Project has moved to https://github.com/CloverHackyColor/CloverBootloader.
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    Downloads: 1,693 This Week
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  • 21
    EmuTOS

    EmuTOS

    Free operating system for Atari computers, and more.

    EmuTOS is a TOS compatible operating system for Atari ST series computers, and more. It is made from Digital Research's GPLed original sources and is a free and open source alternative to Atari proprietary ROMs.
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    Downloads: 443 This Week
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  • 22
    Classic Shell

    Classic Shell

    Start menu and Windows enhancement software

    Classic Shell adds some missing features to Windows 7, 8, 8.1 and Vista like a classic start menu, toolbar for Explorer and others. Note: The software available here is not the latest version. Visit the new website www.classicshell.net to download the latest version and to access the new forums and documentation.
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    Downloads: 228 This Week
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  • 23
    Areca Backup
    Areca-Backup is a file backup software that supports incremental, image and delta backup on local drives or FTP servers. Areca-Backup also allows you to browse your backups and navigate among different version of the files contained in your archives.
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    Downloads: 268 This Week
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  • 24
    FreeArc combines best 7-zip and RAR features: auto-selected LZMA/PPMD/Multimedia compression, 1gb dictionary, exe/dict/delta data filters, updatable solid archives, SFXes, recovery record, AES+Twofish+Serpent encryption, Linux support and much more...
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    Downloads: 365 This Week
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  • 25
    LogicalDOC Document Management - DMS

    LogicalDOC Document Management - DMS

    smart and open source document management system

    LogicalDOC is both document management and collaboration system. The software is loaded with many functions and allows organizing, index, retrieving, controlling and distributing important business documents securely and safely for any organization and individual. Gone are the days when companies used paper-based processes such as printing, mailing and manual filing of paper documents; our document management system replaces all of this with electronic procedures that allow your organization to reduce costs significantly. Check out https://www.logicaldoc.com to learn more. The design of LogicalDOC is based on best-of-breed Java technologies in order to provide a reliable DMS platform. The main interface is web-based, no need to install anything else; users can access the system through their browser. LogicalDOC CE is 100% free software and is packaged with an open source database; while it supports all major DBMS, developers still recommend MySQL for production systems.
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    Downloads: 188 This Week
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