30 years on, it's still alpha, but 0.4.16 brings plenty of bug fixes and quality-of-life improvements - just in time for Windows XP's 25th anniversary
If you're pining away for the days when Windows ran well on 64 MB of RAM, there's a new version of open source NT clone ReactOS promising easier installation and fewer bugs. ReactOS 0.4.16 was announced over the weekend after a year and a half of development, and its list of improvements is substantial. For those unfamiliar with the ReactOS project, it’s a long-running effort (it spun up in 1996) to create an open source equivalent of Windows NT, with the aim of running Windows applications and drivers. If you miss the halcyon days of Windows XP that began a quarter of a century ago, in other words, it's the project for you. Given that it’s an open source project driven by a group of volunteers who’ve had to dodge accusations that they’re just ripping off old copies of a research kernel, compatibility, ease of installation, and stability have all been sore spots for ReactOS. A number of essential elements have been fixed and improved as of 0.4.16, per the team. “We’re excited to showcase the improvements we’ve made,” the ReactOS builders said in their release notes, with “a unified bootcd and livecd image; video, audio, networking, and storage stack improvements; a new installation type; and third-party code syncs” all mentioned as having been added. The unified bootcd and livecd mean a single disc can now be used to boot into a temporary version of ReactOS to have a poke around, and to install the OS itself. A graphical installer is also included in the new unified disk image, meaning that there’s no longer a need to navigate a truly old-fashioned interface to get up and running. Fixed OS functions Running old-fashioned software (or modern iterations of it) on newer hardware is bound to be a complicated mess, and that’s true for ReactOS. Video drivers from “all major … vendors” have been causing issues in the experimental OS for years, the team notes, but apparently one source of the problem has finally been identified and addressed in 0.4.16. The kernel’s system page table entries, it turns out, were filling up when loading third-party graphics drivers because they eat up more memory than most others, so the memory manager layout was modified to increase the number of system PTEs. A different problem with blank OpenGL windows on AMD video drivers was resolved separately. Both improvements “fixed many edge case bugs in our win32k.sys driver,” the ReactOS team noted. A new HD audio bus driver was brought in to replace an older implementation that was never quite finished, addressing frequent bugchecks when attempting to install HD audio controller drivers. As for storage, the 2009 implementation of UniATA gave ReactOS the ability to recognize disk partitions over 8 GB, but the aging driver has since begun to cause slow boot times and load failures. It’s been replaced with a new ATA driver that also allows ReactOS to boot in more environments, including first-generation Hyper-V VMs. A disk cleanup utility was also added. Networking support has also been improved, with support for more adapters and virtual environments added. Asynchronous connections are now supported as well. There’s also a new headless Server Core installation type of ReactOS available with this release that loads a full Win32 subsystem without the GUI, similar to Windows Server Core that Microsoft released with Windows Server 2008. Finally, the ReactOS team has abandoned Windows Server 2003 compatibility restrictions, meaning that its Wine fork designed to interface with Windows-like kernels is no longer limited to Wine 2.x and 3.x, the latest of which was released in 2018. The abandonment of that restriction means ReactOS has been able to update its Wine fork toward Wine 10.0, which was released in early 2025, with 0.4.16 incorporating a significant amount of that work. Support for WineVDM, which increases compatibility for 16-bit Windows applications, was also added in the release. “The mission for ReactOS is to ‘[Run] your favorite Windows applications and drivers in an open-source environment you can trust,’” the team said. “With each release we come closer to fulfilling this goal.” You can download version 0.4.16 of ReactOS here, but the team’s usual warning applies: Despite being a 30-year-old project, it is still in an alpha state “and provides no guarantee of stability, of safety for your files, or that it will work at all on your hardware.” ®
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