Microsoft KB Archive/236935

= You receive a "fatal error C1001: INTERNAL COMPILER ERROR" error message after you install a Visual Studio 6.0 service pack =

Article ID: 236935

Article Last Modified on 6/2/2005

-

APPLIES TO


 * Microsoft Visual C++ 6.0 Enterprise Edition
 * Microsoft Visual C++ 6.0 Professional Edition
 * Microsoft Visual C++ 6.0 Standard Edition

-



This article was previously published under Q236935



SYMPTOMS
After installing a Visual Studio 6.0 Service Pack, existing projects may give the following error message when they are built: <..path\filename>(line #) : fatal error C1001: INTERNAL COMPILER ERROR (compiler file 'msc1.cpp', line 1794) Please choose the Technical Support command on the Visual C++ Help menu, or open the Technical Support help file for more information.



CAUSE
The compiler has problems parsing a precompiled header file created before the installation of the Visual Studio 6.0 Service Pack. The compiler was updated by the Service Pack and the new version does not correctly handle the PCH files created by the original compiler.



RESOLUTION
Delete all of the temporary files created by the previous compiler version.

To clean out a project's temporary files using the Visual C++ IDE, open the project and select Clean from the Build menu.



MORE INFORMATION
In addition to the C1001 error, there might be other symptoms. The symptoms you will see depend on factors that have not yet been identified. The following are some of the symptoms that have been seen:  You may get a message such as the following:

This program has committed an Illegal Operation.

Which may be followed by something similar to:

CL caused an invalid page fault in module at 0000:000000BF

 You may get a Windows 95 blue screen. This would likely be a recoverable blue screen rather than one that forces a system restart. You may also see Error executing Cl.exe in combination with the other errors.

In all cases, the solution is to not compile or build an application after installing Visual Studio 6.0 Service Packs without first cleaning out all temporary files.

A Rebuild All is safe since it cleans out the temporary files before doing a build.

