Troubleshooting UNC-Related Problems (IIS 6.0)

Applies To: Windows 7, Windows Server 2008, Windows Server 2008 R2, Windows Vista

Every technology has its own set of benefits and accompanying difficulties. Problems associated with storing content on remote servers are often network- or authentication-related. These problems are addressed in the following sections: stale content being served, IIS Manager not showing remote content, changes in the support for mapped drives, and the role of offline files.

Stale Content Served

If IIS serves stale content, you can disable the appropriate cache, static or ASP, as a troubleshooting technique. If IIS is using last-modified time as the means for updating the cache, ensure you have waited the default five seconds (or the configured interval) for the cached item to be refreshed.

To disable ASP file caching

  1. Open IIS Manager.

  2. Right-click <ComputerName>, where <ComputerName> is the name of your computer, and then click Properties.

  3. Click Edit to edit the WWW Service Master Properties.

  4. On the Home Directory tab, click Configuration.

  5. On the Process Options tab, select the Do not cache ASP files option.

  6. Click Apply, and then click OK to save your changes.

  7. Restart IIS.

To disable static file caching

Add the following value to the registry:


DisableMemoryCache: REG_DWORD: 1

You need to restart the server for this setting to take effect.


Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use the Registry Editor at your own risk.

For more information about how to disable the static file and ASP template caches, see this Knowledge Base article:;EN-US;q250925.

UNC Files Not Shown in IIS Manager

When using IIS Manager to create virtual directories or Web sites mapped to a remote file server, you may notice what seems to be some confusing error messages and behavior. You may see the error “Logon Failure: Unknown user name and password” or “The system cannot find the path specified.” Also, IIS Manager may simply not show files that are present, yet when you access the virtual directory with the URL in Microsoft Internet Explorer, the files are delivered without error.

This occurs because IIS Manager uses the currently logged on user, such as the Web Administrator to access the remote content, rather than the credentials provided when you created the Web site or virtual directory. You will notice that if you create a connection to the file server with net use (or any other means that creates a connection in the user context of the signed on user), IIS Manager suddenly shows the files. You can eliminate this problem by configuring the file server so that the IIS administrator has rights to read the remote file system.

To verify you’ve configured your site or virtual directory correctly, make some requests with a Web browser to remote content. Unless properly configured, IIS Manager is not a reliable way to verify that your customers are able to access the remote content.

Mapped Drives Will Not Work

For security concerns, services cannot use drives mapped via the credentials supplied by another logged on user. In IIS 5.0, you could potentially get this to work, but it is not recommended. In Windows XP, Windows 2003 Server, and future versions of Windows, services cannot use these mapped drives. For more information, see this Knowledge Base article:;en-us;Q180362

Indexing Service Does Not Support UNC Content

As of this writing, Indexing Service on Windows Server 2003 only supports indexing of local content; therefore, UNC content searching is not supported. In addition, FrontPage Server Extensions 2002 on Windows Server 2003 no longer includes the Wide Area Information Server (WAIS) search engine, which is used by FrontPage webs that use a search component. As the currently recommended replacement is to use Index Service in place of WAIS, FrontPage webs using the search component will not work on UNC-based storage. See;en-us;203796 for more information about replacing WAIS with Indexing Service.