FIX: ASP.NET Does Not Copy Files from Bin Directory to Temporary ASP.NET Files Folder

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Article ID: 319991 - View products that this article applies to.
This article was previously published under Q319991
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After you compile your Web application, you may receive the following error messages in the Microsoft Visual Studio .NET task list:
Could not copy temporary files to the output directory.
The file 'bin\mywebapp.dll' cannot be copied to the run directory. The process cannot access the file because it is being used by another process.
The file 'bin\mywebapp.pdb' cannot be copied to the run directory. The process cannot access the file because it is being used by another process.
Additionally, the ASP.NET worker process (Aspnet_wp.exe) may hold a lock to dynamic-link libraries (DLLs) in the Bin directory.


Typically, this problem occurs because of a trailing backslash at the end of the path that is set for the root Web site. For example:
This causes the mechanism that copies the DLLs from your Bin directory to the Temporary ASP.NET Files folder to fail. When this mechanism fails, the runtime loads the DLL directly from the Bin directory rather than from the Temporary ASP.NET Files folder.

This problem may also occur if any virtual directories with trailing backslashes have child directories that are marked as Web applications.

For more information about whether a trailing backslash causes this problem, see the "More Information" section.


To resolve this problem, obtain the latest service pack for Microsoft .NET Framework. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
318836 INFO: How to Obtain the Latest .NET Framework Service Pack
The English version of this fix should have the following file attributes or later:
   Date         Time   Version             Size   File name
   26-Mar-2002  04:35  1.0.3705.213      192,512  Aspnet_isapi.dll
   26-Mar-2002  04:30                     19,332  Aspnet_perf.ini
   26-Mar-2002  04:35  1.0.3705.213       24,576  Aspnet_regiis.exe
   26-Mar-2002  04:35  1.0.3705.213       28,672  Aspnet_wp.exe
   20-Mar-2002  12:31                      8,709  Smartnav.js
   20-Mar-2002  12:31                      7,003  Smartnavie5.js
   26-Mar-2002  13:34  1.0.3705.213    1,183,744  System_web.dll
NOTE: This fix requires Microsoft .NET Framework Service Pack 1.


To resolve this problem in all circumstances, remove the trailing backslash from the path that is set in the Internet Service Manager.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft .NET Framework Service Pack 2 (SP2).


To verify whether a trailing backslash causes this problem, follow these steps:
  1. Add the following code to a Microsoft Active Server Pages (ASP) page that is located in the same directory as your ASP.NET Web application:
    <%= Request.ServerVariables("APPL_PHYSICAL_PATH") %>
  2. View the page in your browser. Notice that the path includes two backslashes (for example, C:\Inetpub\wwwroot\\mywebapp).

    The presence of two backslashes indicates that you included a trailing backslash in the path in Microsoft Internet Information Services (IIS). In this case, C:\Inetpub\wwwroot\\mywebapp indicates that you included a trailing backslash in the path of the root web.
NOTE: If you include extended or escapable characters in the physical path (such as # or %), you cannot copy the DLL. In this case, the DLL also fails to load.


Article ID: 319991 - Last Review: September 27, 2005 - Revision: 2.3
  • Microsoft ASP.NET 1.0
kbhotfixserver kbqfe kbbug kbdeployment kbfix kbhttpruntime kbnetframe100presp2fix kbnetframe100sp2fix KB319991
Retired KB Content Disclaimer
This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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