Installation of VTune update 9 'slightly' trashed the path in VS.
My prior update of Parallel Studio XE did the same thing (could have been the VTune component)
The Parallel Studio XE update symptom was that some of the .DLLs that my app uses could not be located in Debug run nor other build configurations.
The VTune update resulted in the same thing.
In inspecting environment variables via Control Pannel | System... the required path is present.
However, in using the VS Property manager to observe the path, the path is truncated.
I am not sure as to if this is a VS issue or a VTune/PS XE installation issue where the project property for PATH has a buffer size problem. In my case PATH= contains ~3755 charactes.
Please check your code to see if it uses a fixed size buffer for manipulating PATH in the Project Property within Visual Studio during installation.