Showing category results for MSIX

Oct 20, 2026
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Activatable Extension Points

Howard Kapustein

We often talk about "running an application", "launching an app", or "starting an app". This conjures up visions of spinning up a new process, giving the application life. For packaged applications, Windows has a specific term for bringing an application to life: activation. Bringing a packaged process to life involves more than ordinary unpacka...

Oct 13, 2026
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Is it MSIX? Part 3: Find Package and Application Identity with TASKLIST and PowerShell

Howard Kapustein

We previously determined how to programmatically retrieve a packaged process' package and application identity. Now let's find MSIX package identity using existing tools. TASKLIST.EXE Using the packaged app from our previous example, we know the "image name" (aka executable filename) and that its PID (process ID) is 7664. lists packaged proces...

Oct 6, 2026
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Is it MSIX? Part 2: Finding Package Identity with APIs

Howard Kapustein

We previously determined how to tell if a process is packaged or unpackaged using Task Manager. Now let's find its package and application identity in code. Windows provides APIs to retrieve package and application identity for a process: If you prefer WinRT: Kernel mode What about kernel mode? Nearly all MSIX APIs require a user-mode calle...

Sep 29, 2026
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Is it MSIX? Part 1: How to Tell if a Process Is Packaged

Howard Kapustein

Overheard in a recent conversation: Enterprise Administrator: "The ***redacted*** application is awesome, but it really should be an MSIX package." Microsoft Developer: "Ummm, it already is." That sparked another question: How can you tell if an application is packaged or unpackaged? Turns out there's a few simple w...

Sep 22, 2026
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Footprint vs Payload files

Howard Kapustein

Payload files Payload files are files stored in and delivered by the package. This includes your code, assets, and data, such as executables, DLLs, images, configuration files, and resources. For example: Content files The term content is sometimes used in MSIX-related APIs and documentation, but it does not provide as clean a classifica...

Sep 15, 2026
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PackageType: Main, Framework, Resource, Optional, Bundle

Howard Kapustein

Every MSIX package is one of four package types: MSIX also supports Bundle packages. Bundles are somewhat different from those four package types: a Bundle is a container for one or more MSIX packages. Windows APIs nevertheless expose Bundle alongside the other package types when identifying packages. Each package type has its own behavior...

Sep 8, 2026
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MSIX PackageVolume: How Package Storage Works

Howard Kapustein

An MSIX package can be staged in several ways and locations: By far the most common is PackageVolume. We'll dig into the rest in future posts, but for now let's focus on MSIX PackageVolume. In the beginning... When MSIX first appeared in Windows 81 packages would be staged to a unique directory under . More specifically, packages were pl...

Sep 1, 2026
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Servicing While In Use and ERROR_PACKAGES_IN_USE

Howard Kapustein

How does MSIX service a package while it's in use? Simple: It doesn't. A core principle of MSIX servicing is: Do not service a package while it's in use. Deployment provides several ways to deal with that constraint. Options range from terminating applications to deferring servicing until the package is no longer in use. How hard can it be? '...

Aug 25, 2026
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What Kind of Packaged Process Is It?

Howard Kapustein

As previously discussed, we can divide processes into the two broad categories of packaged vs unpackaged, based on if the process HAS or LACKS package identity. Packaged processes can be divided into three broad categories: All three have package identity, but they make different tradeoffs between compatibility and modern packaged behavior....

Aug 18, 2026
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What’s a PFN?

Howard Kapustein

What's a PFN? MSIX introduced Package identity in Windows 8. While the familiar package identity "5-tuple" was functional, it wasn't especially convenient to pass through APIs or embed in resources such as files, registry keys, URLs, or XML documents. To address this, Windows defined an opaque string representation known as a Package Moniker. Win...