I’m one of the few developers at my company that is using Windows 7. Most of the projects in the solution I am working with are C#, but some are C++. Periodically I get the following error building every single source file in the C++ project on my machine:
fatal error C1859: 'Debug\MyProject.pch' unexpected precompiled header error, simply rerunning the compiler might fix this problem
Nothing I did seemed to solve the problem short of rebooting, which seems to be a common experience (see here and here). Today I stumbled upon a post on the Visual C++ Team Blog that explains what is going on.
It turns out that the anti-malware improvements in Windows 7 are the culprit. PCH files are implemented basically as a memory dump, including pointers. This worked fine on previous versions of Windows, but Windows 7 upped the ante making this approach unworkable.
The new behavior that fixes this problem is available in Visual Studio 2010. The Visual C++ team has also released a hotfix for Visual Studio 2008 SP1 with the fix.