Registry settings missing on app launch, but exists in User.dat in msix package

I'm trying to repackage an application that I've previously used App-V to repackage and deploy.


I verified that the changes in registry under HKCU are contained in MSIX package.


When installing and launching the msix package the changes that should be there are not. It reverts to the application default. This was on a clean VM. No residual registry data for the msix package to merge with.


Manually mounting and browsing the User.dat from the msix package confirms that the data is indeed in the package. Any ideas or pointers?


W10 v1909

Latest MSIX Packaging Tool

PsfTooling v4.5

1 Reply

@pysjkrig It all depends on how the app accesses HKCU.


First of all, when you get to the 2004 or 20H2 version of the OS for deployments, the basic MSIX runtime treats HKCU access better than prior versions.  This could be enough to solve the issue if the app wants to open the HKCU keys and items for read/write alone.


But some apps blindly ask for additional permissions that they don't need.  The app always worked when natively installed or under App-V, as the app could do anything it wanted under HKCU.  MSIX, even under OS2004, does not.


It may be possible to use process monitor against the packaged app and look for access permission issues in HKCU.  Some of those may be addressed using PsfTooling and the RegLegacyFixup.