Back to "Cannot create/shadow copy 'VariousFileName' when that file already exists"
Solution One: Compile Solution of Cannot create/shadow copy
Solution Three - w3p or aspnet to cannot create shadow copy when that file exists
This is the web.config solution for this problem: adding <hostingenvironment shadowcopybinassemblies="false">to the system.web element of your web.config file.
The 'shadowCopyBinAssemblies' property is described as follows: Sets a Boolean value indicating whether the assemblies of an application in the Bin directory are shadow copied to the application's ASP.NET Temporary Files directory.
Setting this to false usually fixes the shadow copy error - Finally, there's a third way.
Alternate Solutions to Consider