Make sure you haven't inadvertently deleted, renamed, or removed the pch.h header file or pch.cpp source file from the current project. (In older projects, these files may be named stdafx.h and stdafx.cpp .)

Make sure the pch.h or stdafx.h header file is included before any other code or preprocessor directives in your source files. (In Visual Studio, this header file is specified by the Precompiled Header File project property.)

You can turn off precompiled header use. If you turn off precompiled headers, it may severely impact build performance.

To turn off precompiled headers

To turn off precompiled header use in a project, follow these steps:

In the Solution Explorer window, right-click the project name, and then choose Properties to open the project Property Pages dialog.

In the Configuration drop-down, select All Configurations .

Select the Configuration properties > C/C++ > Precompiled Headers property page.

In the property list, select the drop-down for the Precompiled Header property, and then choose Not Using Precompiled Headers . Choose OK to save your changes.

In the Solution Explorer window, right-click the pch.cpp source file in your project. (In older projects, the file may be named stdafx.cpp .) Choose Exclude from Project to remove it from the build.

Use the Build > Clean solution menu command for each configuration you build, to delete any project_name.pch files in your intermediate build directories.

See also

Precompiled header files
/Yc (Create precompiled header file)
/Yu (Use precompiled header file)