Monday, September 25, 2023

MSIX - all-in-one-page

The new Microsoft Packaging format MSIX is now out for quite a while. And it improves over time even. It had its heritage in the old AppV format originally coming from Softgrid which was an Microsoft acquisition of Softricity back in 2006. 

The principle is to sandbox an application from the system. So each application had its own virtual registry and filesystem. Everything there will "overwrite" which is already present in the OS or append when it is not part of the OS.

The OS registry and filesystem is not changed. The virtual registry and filesystem lives in a layer between the app and the OS and is "wrapped" with the app. So the OS is not aware of all the content of the virtual registry and filesystem.

Credits: DALL-E 2 and myself :-)


Key features

  • Reliability. MSIX provides a reliable install boasting a 99.96% success rate over millions of installs with a guaranteed uninstall.
  • Network bandwidth optimization. MSIX decreases the impact to network bandwidth through downloading only the 64k block. This is done by leveraging the AppxBlockMap.xml file contained in the MSIX app package (see below for more details). MSIX is designed for modern systems and the cloud.
  • Disk space optimizations. With MSIX there is no duplication of files across apps and Windows manages the shared files across apps. The apps are still independent of each other so updates will not impact other apps that share the file. A clean uninstall is guaranteed even if the platform manages shared files across apps.


  • Package existing Windows apps. Use the MSIX Packaging Tool to create an MSIX package for any Windows app, old or new. The MSIX packaging tool streamlines the packaging experience, offering an interactive user interface or command line to convert and package Windows apps.
  • Install MSIX app packages. Use App Installer to install or update any MSIX app package that is locally available or on any content distribution network.
  • Apply run time fixes to packaged apps. The Package Support Framework is an open source kit that helps you apply fixes to your existing desktop app when you don't have access to the source code, so that it can run in an MSIX container.
  • Use MSIX anywhere. With the open source MSIX SDK, MSIX packages are more versatile, and platform independent. The SDK provides all of the APIs needed to verify, validate, and unpack an app package on any platform, including Windows 10 and non-Windows 10 platforms.

Source and to learn more about the format checkout this page:
What is MSIX? - MSIX | Microsoft Learn´

Great tools to do the packaging are:

1. Microsoft Packaging Tool:
MSIX Packaging Tool Overview - MSIX | Microsoft Learn

2. Another great 3rd party tools is coming from Advanced Installer.
There checkout especially the new free express edition:
Advanced Installer Express Edition

It complement's the MSIX packaging tool from MS with:

  • Shortcut arguments
  • One-click digital signature support
  • Detection of high-level constructs, like file type associations or firewall rules and mapping those entries accordingly in the AppXManifest file
  • PSF (Package Support Framework) integration
  • Generate a conversion project: reload, edit and rebuild your MSIX package in seconds
  • Build MSIX and MSI/EXE packages from the same project

Important and helpful tools even from 3rd party checkout here:

3. "Hover" this is a great FREE tool to work on the application virtualization layer from within the package. Which is normally hard to reach. Checkout this great free tool from AdvancedInstaller

Hover: Launching apps inside a MSIX/App-V container (

4. "MSIX Troubleshooter" this is another great FREE tool from Advanced Installer team to support troubleshooting of MSIX packages. Checkout another great free tool from Advanced Installer
Troubleshooting MSIX installations (

5. And whenever you need even more tweaks you can benefit from the Package Support Framework (PSF) which is an open source community project to further tweak the MSIX format and circumvent issues as we did in the good old days of Windows 7 App compat shims.

5.1 Overview: Framework zur Paketunterst├╝tzung (Package Support Framework, PSF) - MSIX | Microsoft Learn

5.2 Source: Releases · microsoft/MSIX-PackageSupportFramework (

5.3 GUI supporting configuration of PSF TMurgent-PsfTooling - Microsoft Store Apps (Kudos to Tim Mangan to support this great tool!)

Happy MSIX-packaging!