Upgraded AppSDK 0.8 App crashes on startup - Unable to load DLL 'Microsoft.UI.Xaml.dll' or one of its dependencies

[ivberg]

Describe the bug
Upgraded working 0.5.7 ReUnion app to 0.8. This app also used to run fine on 0.8 Preview.

Now it crashes on startup. I had a PITA time in order to try debug it and find the exception (due to running app as admin issues) but I temporarily removed that since the app appears to crash before it hits my code.

Indeed, now I can see it crashes on basic startup.

System.DllNotFoundException
HResult=0x80131524
Message=Unable to load DLL 'Microsoft.UI.Xaml.dll' or one of its dependencies: The specified module could not be found. (0x8007007E)
Source=
StackTrace:

Steps to reproduce the bug

1. Presumably you repro this with a C# 0.8 app created from scratch. However, I am repro'ing on my existing app
2. Launch app, it crashes on startup before even running InitializeComponent(); in MainWindow.xaml.cs

Expected behavior
App doesn't crash on startup and all necessary .dlls are deployed

Screenshots

Version Info
PackageReference Include="Microsoft.ProjectReunion" Version="0.8.0" />
PackageReference Include="Microsoft.ProjectReunion.Foundation" Version="0.8.0" />
PackageReference Include="Microsoft.ProjectReunion.WinUI" Version="0.8.0" />

NuGet package version:
See above

Windows 10 version	Saw the problem?
Insider Build (22000.41)	Yes

Additional context

[ivberg]

Callstack:
[Managed to Native Transition]
System.Private.CoreLib.dll!System.Runtime.InteropServices.NativeLibrary.LoadByName(string libraryName, System.Runtime.CompilerServices.QCallAssembly callingAssembly, bool hasDllImportSearchPathFlag, uint dllImportSearchPathFlag, bool throwOnError) Unknown

System.Private.CoreLib.dll!System.Runtime.InteropServices.NativeLibrary.LoadLibraryByName(string libraryName, System.Reflection.Assembly assembly, System.Runtime.InteropServices.DllImportSearchPath? searchPath, bool throwOnError) Line 14 C#
System.Private.CoreLib.dll!System.Runtime.InteropServices.NativeLibrary.Load(string libraryName, System.Reflection.Assembly assembly, System.Runtime.InteropServices.DllImportSearchPath? searchPath) Line 94 C#
Microsoft.WinUI.dll!WinRT.DllModule.DllModule(string fileName) Line 153 C#
Microsoft.WinUI.dll!WinRT.DllModule.Load(string fileName) Line 133 C#
Microsoft.WinUI.dll!WinRT.BaseActivationFactory.BaseActivationFactory(string typeNamespace, string typeFullName) Line 275 C#
Microsoft.WinUI.dll!Microsoft.UI.Xaml.Application._IApplicationStatics._IApplicationStatics() Line 270 C#
[Native to Managed Transition]
[Managed to Native Transition]
System.Private.CoreLib.dll!System.RuntimeType.CreateInstanceDefaultCtorSlow(bool publicOnly, bool wrapExceptions, bool fillCache) Line 4005 C#
System.Private.CoreLib.dll!System.Activator.CreateInstance<Microsoft.UI.Xaml.Application._IApplicationStatics>() Line 151 C#
Microsoft.WinUI.dll!WinRT.WeakLazy<Microsoft.UI.Xaml.Application._IApplicationStatics>.Value.get() Line 206 C#
Microsoft.WinUI.dll!Microsoft.UI.Xaml.Application._IApplicationStatics.Instance.get() Line 274 C#
Microsoft.WinUI.dll!Microsoft.UI.Xaml.Application.Start(Microsoft.UI.Xaml.ApplicationInitializationCallback callback) Line 282 C#
MyAppUI.dll!MyAppUI.Program.Main(string[] args) Line 26 C#

[ivberg]

This is not good - this also repros on a blank new WinUI project created with the 0.8 templates.

Background:
I see that there is also now a new ReUnion 0.8 VSIX and I upgraded to that as well as checked all new manual upgrade steps.
https://docs.microsoft.com/en-us/windows/apps/windows-app-sdk/update-existing-projects-to-the-latest-release
https://docs.microsoft.com/en-us/windows/apps/windows-app-sdk/stable-channel

Same exact crash on startup as my app above

It's looking for a Microsoft.UI.Xaml.dll and I don't see that in the deployed app folder.

[asklar]

Do you have the package project set as startup or the app? should be the package project

[asklar]

There is a different bug that will crash reunion 0.8 apps in insider builds, tracked by microsoft/microsoft-ui-xaml#5295

[iceberg1370]

Pkg project

[JonPerkinsOldGit]

I had the same problem, but running "Clean Solution" solved it for me :-)

[btueffers]

Please try 0.8.1 to verify if the issue is resolved! Please re-open if you're still facing the problem.

[ivberg]

Yes - verified it's now resolved in 0.8.1!

[seanocali]

I'm getting this on 1.0.0-preview3.

[stewienj]

I'm getting this on 1.0.0-preview3.

I'm not getting this issue on my dev machine, but when I copy my app (unpackaged) to a virtual machine for testing, and install the Microsoft.WindowsAppRuntime.Redist.1.0.0 I seem to be missing this file that exists on my dev machine (as reported by event viewer):
C:\Program Files\WindowsApps\Microsoft.WindowsAppRuntime.1.0-preview3_0.297.2018.0_x64__8wekyb3d8bbwe\Microsoft.ui.xaml.dll

(edit) However this is not the case, because I confirmed using procmon64 that the above DLL is being successfully loaded. Event Viewer is saying it is unable to load Microsoft.ui.xaml.dll in XamlCheckProcessRequirements()

I was following the instructions on this page https://docs.microsoft.com/en-us/windows/apps/winui/winui3/create-your-first-winui3-app?tabs=csharp%2Ccsharp-unpackaged#instructions-for-winui-3-unpackaged-desktop-apps excluding installing the VS2019 extension because my test VM is not a development machine.

[devlead]

I'm getting this too on my Windows 10 VM, but works fine on Windows 11 Desktop, VM and Surface GO 3 Win11.

[seanocali]

I'm running Windows 10, not a VM.

[tinmac]

Im having this issue with a W10 instance running on Hyper-V. All (correct) dependencies installed.

Would be benefficial to be able to test apps on Hyper-V.

[tinmac]

The solution was to install VCRedist . Testing WinUI 3 desktop apps in Hyper-V works fine now thanks to @MikeHillberg's comment

[seanocali]

Reinstalling VCRedist didn't solve this for me. Now on WindowsAppSDK 1.0 still have the problem.
EDIT: I switched to a single-project package and am not experiencing the problem.

[yshteinm]

When I run Packaged app on my machine it works. When I run Unpackaged app it doesn't. When I run exe from console it doesn't work. When I deploy an app to another machine it doesn't work. When I say it doesn't work it means I am getting an error either in Event Viewer or dialog box "Unable to load DLL 'Microsoft.ui.xaml.dll' or one of its dependencies".
I am running Released version 1.0.0

[jeremyVignelles]

@yshteinm : Did you find a solution for your issue ? It seems your comment gets upvoted, so I'm not alone having that issue, but is there an issue I can follow ?

[yshteinm]

@jeremyVignelles I gave up on WinSDK project and doing .Net 6 Core Win Forms

[rossirpaulo]

This is ridiculous. It should not be closed.

[davidbuckleyni]

Im still having the issue in 2023

System.DllNotFoundException: 'Unable to load DLL 'Microsoft.ui.xaml.dll' or one of its dependencies: The specified module could not be found. (0x8007007E)'

[christoph-samuel]

Im still having the issue in 2023

System.DllNotFoundException: 'Unable to load DLL 'Microsoft.ui.xaml.dll' or one of its dependencies: The specified module could not be found. (0x8007007E)'

I'm having the same issue...
Can someone help please?

[mlynch]

Okay so I just updated a project from WindowsAppSDK 1.0.2 to 1.3.0 and I ran into this issue immediately, but I was able to resolve it. I did these things:

• Update VS 2022 (I had an update available)
• Change all references to to the exact version of WindowsAppSDK as shown in the samples (ex: https://github.com/microsoft/WindowsAppSDK-Samples/blob/main/Samples/Input/cs-winui/Input.csproj)
• Updated the WindowsAppSDK runtime: https://learn.microsoft.com/en-us/windows/apps/windows-app-sdk/downloads
• Cleaned my project and restarted

And I was able to get my app to run again. Unfortunately, you can't just set the version to something like 1.3.0 as that breaks everything, you have to use the very specific version as shown in the samples (ex: 1.3.230331000). This feels like something that should be fixed either in docs or in releases.

[krishnainnani]

Did all these still facing the same issue. "Unable to load DLL 'Microsoft.ui.xaml.dll' or one of its dependencies"

[Kakao-Team]

I had the same problem