Error NETSDK1152 on WinUI3 App: Found multiple publish output files with the same relative path: Microsoft.Web.WebView2.Core.dll

Question

1. Installed Visual Studio 2022 (on a clean/fresh Windows 11 installation), installed Template Studio for WinUI (v5.3).
2. Created a Project using Template Studio with these Settings:

- Project type:         Navigation pane
- Design pattern:       MVVM Toolkit
- Pages (Blank pages):
    * Page1
    * Page2
    *
    *
    * Settings page
- Features:
    * Settings Storage  added
    * MSIX Packaging    added
    * Self-Contained    added
    * App Notifications added
    * Theme Selection   added
- Testing: MSTest       not added

3. Installed Microsoft.EntityFrameworkCore.SqlServer (to connect to my SQL Server).

4. After installing Microsoft.EntityFrameworkCore.SqlServer (Latest stable 7.0.4) and immediately after that trying to run an App I get the following error:

Found multiple publish output files with the same relative path:
D:\07_PROJECTS\Kratos365\Kratos365\obj\x64\Debug\net7.0-windows10.0.19041.0\win10-x64\MsixContent\Microsoft.Web.WebView2.Core.dll,
C:\Users\mladen\.nuget\packages\microsoft.web.webview2\1.0.864.35\lib\netcoreapp3.0\Microsoft.Web.WebView2.Core.dll
Kratos365 C:\Program Files\dotnet\sdk\7.0.202\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.ConflictResolution.targets   112

I did noticed whilst installing Microsoft.EntityFrameworkCore.SqlServer that Microsoft.Web.WebView2 (version 1.0.864.35) got installed as well as seen in this screenshot:

Screenshot

But I'm guessing (from the Error) that there is another version of Microsoft.Web.WebView2 in MSIX Packaging in the Project folder.

What I tried:

1. I tried adding the following propertyto my .csproj files, as suggested in this answer here

<PropertyGroup>
 <ErrorOnDuplicatePublishOutputFiles>false</ErrorOnDuplicatePublishOutputFiles>
</PropertyGroup>

But that gave me following error:

Payload contains two or more files with the same destination path 'Microsoft.Web.WebView2.Core.dll'. Source files:
D:\07_PROJECTS\Kratos365\Kratos365\obj\x64\Debug\net7.0-windows10.0.19041.0\win10-x64\MsixContent\Microsoft.Web.WebView2.Core.dll
C:\Users\mladen\.nuget\packages\microsoft.web.webview2\1.0.864.35\lib\netcoreapp3.0\Microsoft.Web.WebView2.Core.dll
Kratos365 C:\Users\mladen\.nuget\packages\microsoft.windowsappsdk\1.2.230313.1\buildTransitive\Microsoft.Build.Msix.Packaging.targets   1504    

2. I tried deleting the 'bin' and 'obj' folders from the Project folder and rebuilding solution but that gave me a bunch of other errors.

3. I tried uninstalling (Start menu > right click on it, uninstall), and then cleaning the solution in Visual Studio before trying to deploy it again, as suggested in this answer here

At this point I tried everything and anything that I could find online - posting a question here is my last resort

Could this be some weird Template Studio for WinUI / Microsoft.EntityFrameworkCore.SqlServer conflict?

Answer 1

In the end the solution was to downgrade Microsoft.EntityFrameworkCore.SqlServer NuGet Package from the Latest stable 7.0.4 down to 6.0.15.

Any version above 6.0.15 (7.0.0; 7.0.1; 7.0.2; 7.0.3; 7.0.4) that contained Microsoft.Web.WebView2 would spit out the Error Found multiple publish output files with the same relative path

I think it was some sort of Microsoft.Web.WebView2 version conflict from MSIX Packaging within Template Studio for WinUI and Microsoft.EntityFrameworkCore.SqlServer NuGet package.