PDB files are built in release mode so you can debug user crashes and
crashdumps.
The vshost.exe is a host application that Visual Studio uses "...to provide
support for improved F5 performance, partial trust debugging, and design time
expression evaluation."

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http://www.peterRitchie.com/blog/
Microsoft MVP, Visual Developer - Visual C#
> Why there are so many *.pdb files in bin/release folder after I compile a c#
> project in VS 2005?
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> http://www.fpsoft.net.cn
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