[Store / MSIX] Automatic update silently overwrites working PowerShell with a broken build on CPUs without SSE4.2 / POPCNT #28406

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest released version
• Search the existing issues.
• Refer to the FAQ.
• Refer to Differences between Windows PowerShell 5.1 and PowerShell.

Steps to reproduce

Summary of the issue

Microsoft Store automatically pushed a PowerShell update (built on .NET 11) onto a system with a CPU that lacks SSE4.2 and POPCNT instructions (x86-64-v2). As a result, a previously working shell was silently replaced with a broken executable that immediately crashes on launch.

Note: This is not a request to revert the x86-64-v2 requirement in the .NET runtime. This is a distribution and packaging bug report regarding how updates are delivered and validated.

Error Output

Fatal error.
The current CPU is missing one or more of the following instruction sets: SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, POPCNT
[process exited with code 2148734214 (0x80131506)]

Why workarounds (like switching to LTS) are not a reliable solution

Manually rolling back to an older version or switching to an LTS channel is not a silver bullet:

1. Store packages update automatically by default, meaning a working installation can be overwritten again at any time.
2. Even when using an LTS branch, there is no guarantee that a future LTS release won't eventually rebase onto a newer .NET runtime with the same x86-64-v2 requirement, silently breaking the environment all over again without prior warning.

Expected Behavior

• The MSIX installer / Microsoft Store update mechanism should validate required CPU instruction sets (x86-64-v2 / SSE4.2 / POPCNT) before applying an update.
• If the host CPU does not meet the hardware requirements, the update should be blocked or skipped, leaving the last compatible version intact and functional.
• At a minimum, the user should receive a clear compatibility warning instead of having a critical automation tool silently broken in the background.

Environment

• Installation method: Microsoft Store (MSIX)
• OS: Windows 10 (x64)
• CPU Architecture: x86-64-v1 (lacks SSE4.2 / POPCNT)

Expected behavior

PS>

Actual behavior

Fatal error.

Error details

Environment data

Fatal error.

Visuals

No response