This update introduces the to Windows 8.1 and Windows Server 2012 R2.
If you ever need to install a new app compiled with Visual Studio 2015–2022 on that old 8.1 machine, you have KB2999226 installed first. windows8.1-kb2999226-x64
The latest VS 2022 runtimes may include their own bundled UCRT. Some apps ship the DLLs locally. However, best practice is still to install the OS-level update. How to Check If It’s Installed Method 1 – Command line: This update introduces the to Windows 8
Let’s pull back the hood. File Name: windows8.1-kb2999226-x64.msu Release Date: September 9, 2014 Size: ~1.3 MB (small, but mighty) Some apps ship the DLLs locally
Windows 8.1 reached end of life on . No more security updates. But many legacy systems (industrial control, medical devices, air-gapped networks) still run 8.1.
dism /online /get-packages | findstr "2999226" Look in C:\Windows\System32\ for ucrtbase.dll . If it exists and its version is 10.0.10240.16384 or higher, you have the update. The Bottom Line windows8.1-kb2999226-x64 is a runtime infrastructure update , not a typical bug fix. It bridged the gap between Windows 8.1 and the modern Windows 10 app ecosystem.
Without KB2999226, those applications would immediately fail on launch with: