c:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1558,9): error MSB3091: Task failed because "AxImp.exe" was not found, or the correct Microsoft Windows SDK is not installed.

I tried to upgrade by application to MVC 5, got into problems and rolled back to MVC 4.

Now however when I try to build my application, I get this error;

c:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1558,9): error MSB3091: Task failed because "AxImp.exe" was not found, or the correct Microsoft Windows SDK is not installed. The task is looking for "AxImp.exe" in the "bin" subdirectory beneath the location specified in the InstallationFolder value of the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SDKs\Windows\v7.0A. You may be able to solve the problem by doing one of the following:  1) Install the Microsoft Windows SDK.  2) Install Visual Studio 2010.  3) Manually set the above registry key to the correct location.  4) Pass the correct location into the "ToolPath" parameter of the task.

I have looked into the registry key, and AxImp.exe can be found in C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\ on my local server, but not in my build server.

However the application was building OK before as an MVC 4 application, so why is this happening now, and how do I fix it?