This is a very crucial feature, but more importantly, optional. Build 15042, the latest Windows 10 Insider Fast Ring build for PC, has an interesting option hidden within the settings. The option is disabled by default but exists on every Windows 10 SKU – including Enterprise.
The option is to block Win32 app execution; controversial, to say the least.
Win32 v/s UWP
If the term ‘Win32’ confuses you, fret not. It’s the framework that supports every app or game you have used on Windows in the past two decades. It’s Google’s Chrome, Steam, the random tools, even Microsoft Office and various other applications and services.
The Win32 framework is the foundation of every Windows app – until Microsoft introduced the Unified Windows Platform with Windows 10.
The UWP framework is modern and comes with many new unique features, but most importantly, is far more secure. A UWP app executes within a bubble – a sandbox – that cannot do anything on the PC without user consent.
Installing a UWP app is only possible – for now – via the Windows Store. That’s not a technical limitation, but an artificial one imposed by Microsoft.
Blocking Win32 apps
The inherent limitations of UWP make it more secure than Win32. Win32, by design, allows applications to do absolutely anything with the PC.
Microsoft introduced the infamous User Account Control with Windows Vista to act as a band-aid for this issue. The UAC restricted certain parts of the filesystem to administrators only, limiting the scope of the problem, but not quite fixing it.
The flaws in Win32, therefore, make it a highly insecure platform. Unfortunately, while Win32 is admittedly flawed, it’s also been the only way to build apps for Windows until Windows 8.1 came along.
So, while Chrome, Steam, and every other Windows software rely on Win32 – so does that random Windows virus or malware.
This feature once enabled, will block Win32. It will block those random viruses, but it will also block every legitimate Win32 app as well, some of which compete with Microsoft’s products.
This feature will obviously be present in the upcoming Creators Update. However, as mentioned, it will be optional, and disabled by default.
For the moment, Microsoft is testing the waters. Per a few rumors, the company is also working on a new Windows 10 SKU that will block Win32 apps by default but will be a cheaper – perhaps free – version of Windows 10.
The Creators Update, though, is expected to release sometime in late March or early April.