MSIX works on Windows 11 but not 10

WaterPigeon If the reply by LeonPavesic solves this for you it might be the simplest way, although I'm not sure how that solves it. But then I'm not sure why Win10 isn't working either if Win11 works with the same package. There are a few things that are that way, but you didn't mention any of them.  If Walter's suggestion does not work, here are some additional ideas.

It is not unusual for a multi-executable package to get confused with InsalledLocationVirtualization.  This happens when an exe looks to a file handle and queries where that file is.  Even if the file was opened using a path somewhere under the package folder, the reported path WILL be under the redirected root folder.  The app often then asks for an offset from that folder which can confuse things. Using the PSF's MfrFixup in ILV-Aware mode, among other things, will redirect the subsequent request back to the equivalent package path and would likely solve this.

As it is a dll, there are situations where you may need a different solution, although adding in the MfrFixup should cause no harm.  Either the PSF DynamicLibraryFixup, or the AppXManifest extension LoaderSearchOrder to find that dll as well.

If you want the PSF version with MfrFixup, the best way depends on how you are making the package.

• If you are the developer and building yourself, get the PSF components from this repository: GitHub - TimMangan/MSIX-PackageSupportFramework: The Package Support Framework (PSF) is a kit for applying compatibility fixes to packaged desktop applications.  Look to the Wiki there for documentation.
• If you are repackaging using the Microsoft Packaging Tool, then use PsfTooling (free app in Microsoft store) to analyze, inject the Psf Components and configure them for you.

And please let us know what worked for you!

Hi WaterPigeon,

you can try to add the webengineprocess.exe executable to the AllowAllTrustedApps registry key.

This is the least invasive solution and will allow the MSIX package to work on both Windows 10 and Windows 11.

To add the webengineprocess.exe executable to the AllowAllTrustedApps registry key, follow these steps:

1. Open the Registry Editor.
2. Navigate to the following key:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModel\AllowAllTrustedApps

1. Right-click on the AllowAllTrustedApps key and select New > String Value.
2. Enter the following name for the new string value:

webengineprocess.exe

1. Double-click on the new string value and enter the full path to the webengineprocess.exe executable in the Value data field.
2. Click OK to save your changes.

Once you have added the webengineprocess.exe executable to the AllowAllTrustedApps registry key, you should be able to install and run the MSIX package on both Windows 10 and Windows 11.