.loadby not work, but .load works well

Question

When I try to use windbg,

.load C:\\Windows\\Microsoft.NET\\Framework64\\v4.0.30319\\SOS.dll 

works perfectly to load SOS extension.

Answer 1

.loadby needs another argument to define where by is. From WinDbg help:

.loadby DLLName ModuleName

DLLName
Specifies the debugger extension DLL to load. If you use the .load command, DLLName should include the full path. If you use the .loadby command, DLLName should include only the file name.

ModuleName
Specifies the module name of a module that is located in the same directory as the extension DLL that DLLName specifies.

So try

.loadby sos mscorwks ; *** .NET 2
.loadby sos clr ; *** .NET 4
.loadby sos coreclr; *** Silverlight

Note that in some cases it may be impossible for .loadby to find out the full path of the by module, e.g. if the dump was created without full path names (.dump /maR). In that case you have to go back to .load.