Host should inform user about different archs when failing to find framework

[vitek-karas]

Some systems support more than one architecture - for example Windows x86 and x64 on the same machine.
If I install:

• .NET 5 x64
• .NET 3.1 x86

And then I try to run dotnet my31app.dll it will fail to find a framework. This is because the default dotnet on the machine is the x64 one (installed first). The error message doesn't list/mention that there's a x86 one available.

Consider either informing the user of the existence of other architectures on the system, or potentially listing those in the output as well.

Related to #51101.

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Issue Details

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Some systems support more than one architecture - for example Windows x86 and x64 on the same machine.
If I install:

• .NET 5 x64
• .NET 3.1 x86

And then I try to run dotnet my31app.dll it will fail to find a framework. This is because the default dotnet on the machine is the x64 one (installed first). The error message doesn't list/mention that there's a x86 one available.

Consider either informing the user of the existence of other architectures on the system, or potentially listing those in the output as well.

Related to #51101.

Author:	vitek-karas
Assignees:	-
Labels:	area-Host
Milestone:	-

[vitek-karas]

Similar problem applies if DOTNET_ROOT is not set correctly (for example it points to 32bit location) - it will also either fail to load completely or fail to resolve a framework. See #3745 for more details on that.

[vitek-karas]

/cc @richlander