vs2010 debugging: module was built without debugging information?

Getting this message, which is not true

The following module was build either with optimization enabled or without debug information.

And it gives me a path to temp asp.net file as

C开发者_JAVA百科:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\47cdc49a\658f757e\assembly\dl3\0fbfef54\55a1ff8a_28eacb01\MyModule.dll

I open folder and there are three files as expected dll, pdb, and ini. What gives?

Under Debug>Modules this dll was added to excluded list of dll's that should not have symbols loaded. Once I removed it, it works fine.