problems upgrading 0.64.14 -> 0.66.6

[burtonrodman]

Hello,
I'm trying to upgrade my project using the upgrade helper and after applying all the changes, get the following build warnings and errors. I can see that the beginning of the XamlTypeInfo.g.cpp has the namespace "winrt::Windows::UI", but then throughout the rest of the file references "winrt::Microsoft::UI". I am NOT using any experimental features.

0>C:\source\[redacted].vcxproj(27,3): warning MSB4011: "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Microsoft\VC \v170\Microsoft.Cpp.Default.props" cannot be imported again. It was already imported at "C:\source\[redacted].vcxproj (22,3)". This is most likely a build authoring error. This subsequent import will be ignored. 0>C:\source\[redacted]\node_modules\react-native-windows\PropertySheets\JSEngine.props(4,3): warning MSB4011: "C:\source\[redacted]\windows\Exper imentalFeatures.props" cannot be imported again. It was already imported at "C:\source\[redacted].vcxproj (3,3)". This is most like ly a build authoring error. This subsequent import will be ignored.

2>C:\source\[redacted]\Generated Files\XamlTypeInfo.g.cpp(444,39): error C3083: 'UI': the symbol to the left of a '::' must be a type [C:\source\[redacted].vcxproj] 2>C:\source\[redacted]\Generated Files\XamlTypeInfo.g.cpp(444,43): error C3083: 'Xaml': the symbol to the left of a '::' must be a type [C:\source\[redacted].vcxproj] 2>C:\source\[redacted]\Generated Files\XamlTypeInfo.g.cpp(444,49): error C3083: 'Controls': the symbol to the left of a '::' must be a type [C:\source\[redacted].vcxproj] 2>C:\source\[redacted]\Generated Files\XamlTypeInfo.g.cpp(444,59): error C2039: 'TreeViewNode': is not a member of 'winrt::Microsoft' [C:\source\[redacted].vcxproj]

[burtonrodman]

wow, that was a loooong journey! after fixing this compile error, I had 2 full days of issues with the app crashing on launch.

After I literally deleted all of my custom code, removed all packages that didn't come with the stock sample app and did a side-by-side comparison of my code to the sample app, I finally found that some resources in App.xaml were causing the crash...