Calling GetProcAddress on ISAPI filter “aspnet_isapi” failed

On an ASP.NET 4 application on IIS 7 tried has stopped working when szembetaláltuk ourselves to death following yellow:

HTTP Error 500.0 – Internal Server Error
Description: Calling GetProcAddress on ISAPI filter “C: \ Windows \ Microsoft.NET \ Framework \ v4.0.30319 \ aspnet_isapi.dll” failed.
Error Code: 0x8007007f

This is a Windows 7 machine, which has recently been added to the Visual Studio 2010 and IIS 7 as well. Fortunately, the error message gives clues to the solution, and accordingly checked for missing dependencies, NTFS permissions, config files. In fact, we tried aspnet_regiis / i with to see if the installation was a bad sort, but it did not help: (The best part was that VS 2010 is a newly created application also produced the same symptoms.

Finally, we opened a website and ISAPI Filters IIS Manager module and immediately discovered the cause of the error:

aspnet_isapi error

For some inexplicable reason, added to the aspnet_isapi.dll ISAPI filters list. But that does not filter , but extension , it is no accident anyázott IIS!

A quick Remove and everything is solved.