You might think that Windows 11 represents everything modern that Microsoft has to offer the world, but that isn’t always the case. It might feature some exciting new and modern capabilities, like built-in AI (love or hate it) and snappier apps, but some of the underlying framework has yet to be replaced. Some of it, dating back to the late 90’s (Win32 API).
If you are a developer, you likely already know this, unless you were just getting started in the industry. But for everyone else, this might not have been obvious. Windows 11 is essentially a giant modern skin, slapped on top of a very old framework. Sure, the company has made multiple (and huge) moves toward 64-bit everything, but the operating system is far from being a complete 64-bit experience. This is something that Microsoft just recently admitted to in a recent post by Mark Russinovich, Chief Technology Officer (CTO) of Microsoft Azure.
Did anyone expect Win32 to still be going strong in 2026? Mark Russinovich explains why its deep roots in Windows—and the massive ecosystem built on top—have given it serious staying power. Turns out “legacy” can still mean essential.
SysInternals site: https://t.co/BOsLvgAn81 pic.twitter.com/6Yd3ipX42p
— Microsoft Dev Docs (@docsmsft) May 6, 2026
The reason for this is compatibility, beyond everything else, and probably mixed with a slow conversion that has likely run into many obstacles (all new bugs and crashes) over the years. Why? If Microsoft were to completely restart with fresh 64-bit code, all across the board, users would lose access to all of the older apps and games, rendering so many things legacy and no longer natively compatible.
Microsoft actually tried testing the waters with this, back with Windows RT on ARM chips, but it didn’t go so well. The company didn’t provide any resolution to the fact that all of your old software no longer works. That is a massive shock to both consumers and professionals of all levels. Users were limited to the apps from the Microsoft App Store, which didn’t fulfill the needs of everything lost. In fact, there was a huge gap in what you needed vs what was available. It felt more like a tablet environment than a proper PC desktop.
So it came as no surprise that the public was absolutely confused and frustrated with those products, and everything fell flat on its face, sending Microsoft back to the drawing board. Windows is supposed to be an expansive environment that is super configurable and offers support for just about every piece of software you want to throw at it. Windows RT was none of that.
So it continued to build on the original 32-bit foundation that it has had for decades. Expanding upon the size of that snowball that is slowly rolling down a mountain.
If the company were to fully go 64-bit with the operating system (and do it properly), it would see a massive boost to performance. This includes faster startup times, faster app loading, and just snappiness all across the board. Although there would still have to be some exceptions.
When it comes time for Microsoft to move toward a solid 64-bit environment (which would be a complete rewrite of the entire operating system), it might be forced to include micro-VM (sandbox) support for legacy apps/games. This way, it would see a huge speed boost, while still supporting all of the old stuff you don’t want to lose. It would have to be something like Windows Sandbox, but in more of a Sandboxie design/style. So, essentially, it would be a lot like WINE is to Linux, opening each “legacy” app into special emulated windows, likely using a modernized version of WOW64 (which currently helps Windows run 32-bit apps within Windows 11 today).
With Microsoft coming out with this admission in such a public announcement, it might be their cry for help by making it public to anyone who didn’t already know this, to raise awareness and create a new push toward something new that people “might” be willing to accept if they know why the push is there to begin with.
