Can no longer compile any project after upgrading from .NET 9.0 Preview 7 to .NET 9.0 RC1

[MarkCiliaVincenti]

The steps I took:

• Uninstall .NET 9.0 Preview 7
• Install .NET 9.0 RC1
• Upgrade Visual Studio 2022 to the latest version

Every project I try compiling I'm getting this error even though it's not referencing System.Text.Json, even transitively.

C:\Program Files\dotnet\sdk\9.0.100-rc.1.24452.12\Sdks\Microsoft.NET.Sdk\targets\Microsoft.PackageDependencyResolution.targets(266,5): error NETSDK1060: Error reading assets file: Error loading lock file 'C:[....]\obj\project.assets.json' : Could not load file or assembly 'System.Text.Json, Version=8.0.0.4, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified.

I tried redownloading and reinstalling, repairing, deleted the NuGet package cache, manually deleted the bin and obj folders, rebooted the PC... basically everything I could think of

[Youssef1313]

We are encountering this in Uno Platform as well once we updated to RC1

[MarkCiliaVincenti]

What I find strange is the version number. Should it really be 8.0.0.4? The latest stable NuGet package version is 8.0.4

[MarkCiliaVincenti]

We are encountering this in Uno Platform as well once we updated to RC1

Only in Uno Platform though? I'm having this issue in every project. I can start a new solution, add a class library with nothing in it, try to compile and I get that error.

[Youssef1313]

It shouldn't be specific to Uno Platform, just mentioning that we are also unable to upgrade to RC1 due to this issue

[Youssef1313]

This may be related to #40645 ?

cc @Forgind

[MarkCiliaVincenti]

Quite likely, possibly this commit: 337965f

In my SDK folder I have 8 files called System.Text.Json.dll

Four are file version 9.0.24.43107
Two are file version 8.0.724.31311 with a file size of 628 KB
Two are also file version 8.0.724.31311 but have a file size of 566 KB

None of them are 8.0.0.4

[KalleOlaviNiemitalo]

What I find strange is the version number. Should it really be 8.0.0.4? The latest stable NuGet package version is 8.0.4

https://nuget.info/packages/System.Text.Json/8.0.4 shows lib/net8.0/System.Text.Json.dll with full name System.Text.Json, Version=8.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, not assembly version 8.0.0.4. The file version 8.0.724.31311 does not matter for the assembly load error.

https://nuget.info/packages/System.Text.Json/9.0.0-rc.1.24431.7 shows both lib/net8.0/System.Text.Json.dll and lib/net9.0/System.Text.Json.dll with full name System.Text.Json, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51 and file version 9.0.24.43107. I suppose this could be suitable for the referenced assembly version 8.0.0.4 if there were an assembly binding redirection.

[wanggangzero]

I meet this problem too!
to avoid this Exception, you can place a global.json in your project's root folder to specify the version of sdk 8.0.401

[MarkCiliaVincenti]

I meet this problem too! to avoid this Exception, you can place a global.json to specify the version sdk 8.0.401

But then you wouldn't be able to compile .NET 9 projects, no?

[wanggangzero]

I meet this problem too! to avoid this Exception, you can place a global.json to specify the version sdk 8.0.401

But then you wouldn't be able to compile .NET 9 projects, no?

Yes! I think you can down grade it to preview7 first.

[Youssef1313]

Looks like it's a known issue: https://github.com/dotnet/core/pull/9489/files

[MarkCiliaVincenti]

I hoped this App.config would help but it really didn't. Maybe I am missing something.

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
	<runtime>
		<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
			<dependentAssembly>
				<assemblyIdentity name="System.Text.Json" publicKeyToken="cc7b13ffcd2ddd51" />
				<bindingRedirect oldVersion="8.0.0.4" newVersion="9.0.0.0" />
			</dependentAssembly>
		</assemblyBinding>
	</runtime>
</configuration>