The question how to disable IntelliSence in Visual Studio 2005 and Visual Studio 2008 was very popular among programmers some time ago. There was even a huge topic on the MSDN forum where this issue was discussed. Deleting the file feacp.dll appeared to be the right solution.
The developers took this experience into account when working on Visual Studio 2010 and brought significant modifications both into the IntelliSence mechanism itself and means of disabling it.
In Visual Studio 2010, you may disable IntelliSence through the settings page of "Tools|Options" menu: Text Editor->C/C++->Advanced.
Why do we, PVS-Studio analyzer developers, discuss the question of disabling IntelliSence in Visual Studio 2010? Unfortunately, the new IntelliSence "spoils our life a bit". Since this mechanism is new and seems to be not fixed completely, it involves some problems. Sometimes (we did not manage to find out in what conditions), IntelliSence in Visual Studio 2010 adds its messages into Error List at the same time when our analyzer PVS-Studio generates its own messages into this list. It looks as if PVS-Studio writes about IntelliSence. Thus, along with "our" messages
c:\users\ svn\viva64\vivawalker.cpp(1743): error V101: Implicit assignment type conversion to memsize type. c:\users\svn\viva64\vivawalker.cpp(1897): error V112: Dangerous magic number 4 used: eeUtil::Nth(p, 4);.
the same list contains messages which are absolutely out of place:
"c:\program files (x86)\microsoft visual studio 10.0\vc\include\xlocnum", line 1233 (col. 11): error: floating constant is out of range "c:\program files (x86)\microsoft visual studio 10.0\vc\include\xlocnum", line 1234 (col. 13): error: floating constant is out of range
Such messages are often quite senseless. Besides, they are generated not all the time but only in some rare and difficult-to-recall cases. Unfortunately, the only possible solution of this problem (in order to prevent PVS-Studio messages from mixing with those of IntelliSence) is to disable all the features of IntelliSence on the tab mentioned above.
If you do not have unnecessary messages from IntelliSence or they do not prevent you from handling PVS-Studio messages, you may leave IntelliSence enabled.
We hope that Microsoft will fix this issue in time and we will not need to disable IntelliSence.
P.S. There is a very good description of this settings tab in the Visual C++ team's blog.