30 years of ReactOS

[Posted January 22, 2026 by jzb]

ReactOS, an open-source project to develop an operating system that is compatible with Microsoft Windows NT applications and drivers, is celebrating 30 years since the first commit to its source tree. In that time there have been more than 88,000 commits from 301 contributors, for a total of 14,929,578 lines of code. There is, of course, much left to do.

It's been such a long journey that many of our contributors today, including myself, were not alive during this event. Yet our mission to deliver "your favorite Windows apps and drivers in an open-source environment you can trust" continues to bring people together. [...]

We're continuing to move ReactOS forward. Behind the scenes there are several out-of-tree projects in development. Some of these exciting projects include a new build environment for developers (RosBE), a new NTFS driver, a new ATA driver, multi-processor (SMP) support, support for class 3 UEFI systems, kernel and usermode address space layout randomization (ASLR), and support for modern GPU drivers built on WDDM.

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Wish them luck

Posted Jan 22, 2026 18:57 UTC (Thu) by jmalcolm (subscriber, #8876) [Link] (12 responses)

It is easy to be cynical about ReactOS. 30 years is a long time and they are far from "there" yet. And the project has seemed downright hostile to outsiders at times.

But the last year or two have felt more hopeful. Not only did they finally release 0.4.15, surfacing literally years of development but they have opened up to the idea of implementing features newer than Windows NT. They have synced with Wine 10, added NT6 APIs, have a 64 bit port, are adding UEFI, and are even talking about WDDM drivers. Some of the developers seem to care about making ReactOS a project that gets used. A massive network performance boost was announced just the other day.

With all the hostility towards Windows out there now, it may yet not be too late for ReactOS. If they can get a 64 bit port out with enough API support to run modern browsers and maybe an office suite, the momentum could come back. Being able to run WDDM drivers would unlock a massive universe of hardware that cannot run Windows 11 some of which may not be perfect for Linux either.

They have done so much of the hard work already. And Wine has so much to offer to put on top of that. ReactOS could still surprise us and become a viable option.

There is lots of hard work to do of course. And some big challenges like WoW64.

I wish them luck.

Wish them luck

Posted Jan 22, 2026 22:12 UTC (Thu) by WhatsInAName (guest, #128037) [Link] (11 responses)

The unfortunate truth is that they will always be playing catch up. As a result, their system will always be, at best, "almost 100% compatible" with MS's latest and greatest. Which implies that ReactOS will always remain in a very small niche - useful under some, maybe even many, circumstances, but not the kind of thing anybody is likely to adopt as a replacement of Windows.

Usage as build platform ... ?

Posted Jan 22, 2026 22:41 UTC (Thu) by aleXXX (subscriber, #2742) [Link] (1 responses)

As a linux-based open source developer, having an easy way to have a container or VM where I could see whether my software also builds and runs under Windows would be nice. Maybe they could fill such a role ?

Usage as build platform ... ?

Posted Jan 23, 2026 8:21 UTC (Fri) by taladar (subscriber, #68407) [Link]

Not just building, also just testing certain platform specific APIs might be useful, e.g. things like desktop notifications come to mind that just have different semantics on every major platform once you get into the more advanced features.

Wish them luck

Posted Jan 23, 2026 0:00 UTC (Fri) by rgmoore (✭ supporter ✭, #75) [Link] (3 responses)

As a result, their system will always be, at best, "almost 100% compatible" with MS's latest and greatest.

It seems to me that this still leaves them with a potential niche: legacy Windows users. There are a lot of people whose key use for Windows is for programs that were written a long time ago and aren't changing. Those people don't need the latest and greatest, just something that will mean they don't have to deal with the junk Microsoft has shoved into Windows 11. What isn't clear to me is whether those people really need a full Windows clone or if they'd be better off with Wine on Linux.

Wish them luck

Posted Jan 23, 2026 9:04 UTC (Fri) by NYKevin (subscriber, #129325) [Link] (2 responses)

Unfortunately, a lot of industries have some notion of "compliance" or "certification," which (in most cases) rounds to "you can't use anything other than the exact combination of hardware and software that was approved for this purpose." Since ReactOS was not approved, it cannot be used as a substitute for old Windows (in those industries). Yes, you could get it certified, but that is costly and difficult at best (and has to compete with the alternative of "buy the new version that is already certified").

Wish them luck

Posted Jan 23, 2026 11:09 UTC (Fri) by Wol (subscriber, #4433) [Link]

> and has to compete with the alternative of "buy the new version that is already certified"

Although that could be "not fit for purpose", and depending on how key management has changed over the years, I've got a lot of old software that comes with a "permanent" activation key. The ability to install an NT4 or Win2K clone, and then install this software on top using the key stamped on the CD or whatever, would be appreciated.

Although what state that media is in now having been stored in a box for years, I don't know ...

Cheers,
Wol

Wish them luck

Posted Jan 25, 2026 19:51 UTC (Sun) by dsommers (subscriber, #55274) [Link]

> Unfortunately, a lot of industries have some notion of "compliance" or "certification,"

Yes, that is true. At the same time, it is not all the industries requiring a certified Windows OS. I would even dare say, a quite large noticeable amount (close to majority?) of "professional" Windows users does not have such requirements.

What changes the game a bit is that ReactOS is the first more or less realistic alternative OS capable of running Windows binaries (even though still not everything).

Wish them luck

Posted Jan 23, 2026 0:05 UTC (Fri) by DOT (subscriber, #58786) [Link]

If it is stable enough to run Firefox on a laptop without crashing and has decent performance, I think it could be quite attractive. The application compatibility of Wine is quite amazing, sometimes better than the original, for older software.

Wish them luck

Posted Jan 23, 2026 9:04 UTC (Fri) by farnz (subscriber, #17727) [Link]

The question becomes how big that niche actually is. Windows client releases are normally supported for 3 years from the date of release, so being up to 3 years behind "just" puts you in line with the supported Windows versions; if we extend to Long Term Servicing Channel/Branch, that increases to 5 years general support and 10 years security support, so as long as you can avoid being more than 10 years behind, you're keeping up with the trailing edge of supported versions of Windows.

Whether that's a time frame ReactOS can keep up with is a different question, but it's more manageable than "latest and greatest".

Wish them luck

Posted Jan 23, 2026 16:18 UTC (Fri) by jmalcolm (subscriber, #8876) [Link] (2 responses)

> ReactOS will always remain in a very small niche

I do not think that at all. At least, I do not see this as inevitable.

Whenever versions of Windows fall out of support, we see massive percentages of Windows users trying to stay on the previous versions. We saw that with XP, we saw that with Windows 7, and we are seeing ti with WIndows 10. These versions are years behind the "modern" Windows versions but people still want to use them.

Being compatible with the oldest supported version of Windows may be a bigger opportunity than being compatible with the newest one. And, while I am not predicting anything, if some significant percentage (say 25% or more) of Windows users migrated to ReactOS, applicaton developers will probably not drop support for it (or the version of Windows it is compatible with) even if Microsoft does.

There are many users that just want to keep using the software they have. They are not necessarily looking to constantly exploit every new Windows feature.

A big exception to this is gamers but those APIs are well supported in Open Source already and so probably not as hard to keep up with anyway.

And one of the promises of ReactOS is that you will be able to use your Windows drivers, even the proprietary ones. So, if the functionality you need comes from the drivers, you just use it. ReactOS does not need to "keep up" with that.

Windows will always be a better place to use the latest Windows features but that does not mean that ReactOS cannot be useful or even popular.

Wish them luck

Posted Jan 26, 2026 9:58 UTC (Mon) by taladar (subscriber, #68407) [Link] (1 responses)

I am not sure you appreciate the distinction between people who just want to use exactly what they have been using (OS included) vs. people who want to use something that is merely a compatible platform for their old software here. I think the latter group is much smaller and does not include most of the non-technical people staying on old OS versions past their support EOL.

Wish them luck

Posted Jan 26, 2026 17:28 UTC (Mon) by rgmoore (✭ supporter ✭, #75) [Link]

This sounds about right to me. Most people who want to stay on the old version are doing it out of inertia- the old version is working for them and they don't want to go to the bother of changing- rather than because they have something that will only work on an old version of Windows. It's the same reason the hoped for mass migration to Linux by people who don't want to replace their computers with Win11 compatible models hasn't materialized. The low effort path is to stick with Win10 and hope for the best, not to switch to something new that offers security updates.

Ran it!

Posted Jan 30, 2026 4:49 UTC (Fri) by pabs (subscriber, #43278) [Link] (2 responses)

To celebrate I booted the LiveCD on an old Thinkpad x201 (BIOS). Works great, including solitaire.

Couple of roughish edges though. Compared to a Linux distro, hardware support for the touchpad/ethernet was missing, but I didn't bother to go find Windows drivers for them. The startup didn't go straight into a desktop. Turning off the machine from the menu shut down the UI but showed a screen asking you to power off the machine yourself.

Ran it!

Posted Jan 30, 2026 14:51 UTC (Fri) by mathstuf (subscriber, #69389) [Link] (1 responses)

Wasn't that how Windows used to work? Orange text on black, IIRC, saying that it was now safe to power off?

Ran it!

Posted Jan 31, 2026 13:35 UTC (Sat) by neggles (subscriber, #153254) [Link]

Standard behaviour on AT-class systems (as the PC AT only had a hard power switch), many SBCs, and if the OS doesn't have drivers for whatever soft-power-off method the system uses; my guess is it's probably down to not having chipset drivers installed.