This article was previously published under Q180410
For a Microsoft Windows XP version of this article, see 832978.
When you try to start a program on a Microsoft Windows 2000-based computer or a Microsoft Windows NT-based computer, the program may not run. Additionally, when you manually add a new environment variable that contains a path value, the path may be truncated.
This problem occurs because a system environment variable or a user environment variable contains a path that exceeds the maximum character length.
If a system environment variable contains a path that exceeds the maximum character length, the path is truncated when you start a program. This truncated version of the path is then written back to the registry. When this occurs, the operating system may not be able to find the executable files or the DLL files for the program. In this case, the program may not run.
The maximum length of the combined system and user-defined path for an environment variable is 1,023 characters, excluding the "path=" part of either.The system path is limited to a maximum length of 1,023 characters. The user-defined path is limited to a maximum length of 511 characters. When a user-defined path is combined with a system path, the user-defined path is limited to 1,023 characters minus the system path.If the system path uses the total allocated environment space, the user-defined path may be truncated. In this case, you may experience the problem that is mentioned in the "Symptoms" section.
Note These path length limits for environment variables are also true for Microsoft Windows XP and Microsoft Windows Server 2003.
Note After you apply this hotfix, the path length limit for environment variables is increased to 2,048 characters.
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.
To resolve this problem, 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.
You must restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace any other hotfixes.
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.