Reporting Services Tip: Resolving 403.9 Errors on Windows XP

Use this workaround to prevent IIS from locking

Editor's Note: This tip is excerpted from the authors' recently published book, The Hitchhiker's Guide to SQL Server 2000 Reporting Services (Addison-Wesley, 2005). Two sample chapters and a video of this tip's steps are available for download at

By default, the Microsoft IIS server hosted on Windows XP is configured to a maximum of 10 concurrent connections. This limit can be debilitating when developing with SQL Server 2000 Reporting Services on XP because each Web browser connection consumes more than one connection. Once you start to get 403.9 errors, it appears that even when IIS times out and closes those connections (as confirmed by the performance monitor), you can still get strange errors when opening a new connection. However, at this point, these errors are generated by Reporting Services rather than by IIS.

The solution for this problem is to increase the maximum number of connections to 40 by editing the IIS metabase. We used the IIS MetaEdit utility to make the change. Like the registry editor, this tool comes with warnings such as "Beware a professional with a tool." To tune the IIS metabase on your development system, perform the following steps:

  1. Find and download the IIS MetaEdit 2.2 utility. The Microsoft Knowledge Base Article "HOW TO: Download, Install, and Remove the IIS MetaEdit 2.2 Utility" ( should help you locate the tool. Install it and run it.
  2. Next, locate LM | W3SVC in the Metabase Editor, as Figure 1 shows, and double-click the MaxConnections entry to launch the Edit Metabase Data dialog box. In the Data text box, increase the MaxConnections (ID-1014) to a value no higher than 40. If you try to increase the MaxConnections to a value greater than 40, you'll find that it will get the better of you. A MaxConnections value entry is created directly in the LM | W3SVC | 1 node, which is the default Web site, and that value (which you'll find by its ID of 1014) will be set to 10. If this happens to you, you can safely delete the MaxConnections with an ID of 1014 in LM | W3SVC | 1, but only after you have set the MaxConnections value in LM | W3SVC to a number less than 40.
  3. Finally, close the Metabase Edit tool and restart IIS.

We've not had a problem with 403.9 errors since we increased the limit, but if you still are able to lock up IIS in developer scenarios, you might investigate setting the Connection Timeout property to a lower value to decrease the time before IIS detects that a connection is idle and disconnects it. You can set the Connection Timeout property on the Web Site tab of the Default Web Site Properties dialog box, as Figure 2 shows.

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