Troubleshooting IntelliSense in C++ Projects

IntelliSense can stop working under certain conditions. Use the following steps to help determine why IntelliSense does not work for C++ projects.

To investigate IntelliSense failure in C++ projects

Make sure that the Visual C++ project contains no compilation errors.
1. If the project is a Makefile project, see How to: Enable IntelliSense for Makefile Projects.
Make sure that stdafx.h is on the include path. For more information about include paths in Visual C++ projects, see #include Directive (C/C++) and /I (Additional Include Directories).

IntelliSense does not work in C++ projects under the following circumstances:

The cursor is in a code comment.
You are writing a string literal.
A syntax error appears over the cursor.
The solution consists of either the syntax for managed C++, or the earlier Managed Extensions for C++ syntax.
IntelliSense is not fully supported when you reference a header file multiple times by using the #include directive, and the meaning of that header file changes because of various macro states that are defined through the #define directive. In other words, when you include a header file several times and the header usage changes under different macro states, IntelliSense does not always work.