I made a Class Library in VS2017 in .NETCoreApp 1.1, and when I try to load the .DLL from another test project, I get the error
System.IO.FileNotFoundException: 'Could not load file or assembly 'ABC, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.'
And in the output I see
'dotnet.exe' (CoreCLR: clrhost): Loaded 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\1.1.2\mscorlib.dll'. Cannot find or open the PDB file.
Why is it trying to load that .DLL and in case it is required to run (but not build?), why is it not already there?
Why is it trying to load that .DLL?
Everything loads core CLR. That's where types like "int" are defined: the core types that are always required.
why is it not already there?
It is. The core lib is loading successfully. The message is that the debugging information isn't available. PDB files contain information that helps the debugger understand the information in the DLL. If you want the debugging information, install the debugging information.
The other assembly is failing to load for some other reason. Use the fusion log viewer to figure out why.