Unable to copy file reference.dll to bin/reference.dll. The process cannot access the file reference.dll because it is being used by another process

Question

For one of my ASP.NET 3.5 applications, every single time I try to build the web app, it throws the following build errors in Visual Studio 2008:

Error 16

Answer 1

Removing the following lines from my app.config solved this for me - I'm using VS2010.

<runtime>
  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
          <assemblyIdentity name="nunit.framework" publicKeyToken="96D09A1EB7F44A77" culture="neutral"/>
          <bindingRedirect oldVersion="0.0.0.0-2.5.7.10213" newVersion="2.5.7.10213"/>
      </dependentAssembly>
  </assemblyBinding>
</runtime>

Answer 2

I had similar issue and was able to resolve it by changing the 'AssemblyInfo.cs'

Visual Studio build fails: unable to copy exe-file from obj\debug to bin\debug

Answer 3

The issue ended up being that in the web.config someone had added:

hostingEnvironment shadowCopyBinAssemblies="false"

After commenting this out, everything started building ok. What a nightmare!!

Answer 4

I have battled this issue FOR YEARS!

Have you tried adding this to your PREBUILD Event?

if exist "$(TargetPath).locked" del "$(TargetPath).locked"
if exist "$(TargetPath)" if not exist "$(TargetPath).locked" move "$(TargetPath)" "$(TargetPath).locked"

See this for more info: http://nayyeri.net/file-lock-issue-in-visual-studio-when-building-a-project

Here's another thread, with more things to try...

http://social.msdn.microsoft.com/forums/en-US/Vsexpressinstall/thread/5b71eb06-5047-483d-8fd3-b75c102d41e9/?prof=required

Answer 5

This issue commonly occurs when you change your project from one directory to another . For the Shadow copy error you might have added this line in your web.config.To fix this follow the following

In your web.config file if there is something like

<hostingEnvironment shadowCopyBinAssemblies="false" />

change that into

<hostingEnvironment shadowCopyBinAssemblies="true" />

or remove it .Then it will work fine

Answer 6

Use ProcessExplorer to find out what process has the file open and go from there.

If a process is currently using those DLL, you can't delete and re-write it. You'll have to kill or otherwise stop the process using those DLLs while you compile.