FIX: You receive a "fatal error CS0013" error message when you build a Visual C# project in Visual Studio .NET 2003

This article has been archived. It is offered "as is" and will no longer be updated.
When you build a Visual C# project in Microsoft Visual Studio .NET 2003, you receive the following error message:
fatal error CS0013: Unexpected error writing metadata to file 'C:\temp\YourProject\obj\Debug\YourFile.dll' -- 'Unspecified error '
This problem may occur when the Visual C# compiler encounters errors when it emits information about nested types that access the types that contain them.

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Visual Studio .NET 2003 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.


No prerequisites are required.

Restart requirement

You do not have to restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version            Size    File name   --------------------------------------------------------------   22-Jun-2004  10:44  7.10.4174.4       626,688  Cscomp.dll
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
The following is an example of the Visual C# code that produces the error message that is mentioned in the "Symptoms" section:
using System;namespace YourNameSpace{	public class A : B.X {}	public class B	{		public class X : I {}		public class Y {}		public class I {}	}}
For additional information about the standard terminology that is used to describe Microsoft software updates, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates
VS2003 C#

Article ID: 843552 - Last Review: 01/17/2015 10:54:17 - Revision: 2.3

Microsoft Visual C# .NET 2003 Standard Edition, Microsoft Visual Studio .NET 2003 Enterprise Developer, Microsoft Visual Studio .NET 2003 Enterprise Architect, Microsoft Visual Studio .NET 2003 Academic Edition

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