got CA Plex Build Error :LINK : error C1083: Unable to open source ..\xxx.CPP: No such file or directory 
even the file is in the correct defined folder. This only occurs when using REMOTE network drive within MS Visual Studio 2013 since upgrade to CA PLEX 7.2.1. Using local drive there is no error and Build completed.

Application was not Build.

Windows 7 or 10, CA Plex 7.2.1 , MS Visual Studio 2013

Problem solved after installed Visual Studio update 5 which is required for Plex 7.2.1
 

https://docops.ca.com/ca-plex/7-2-1/en/installing/system-requirements
Notes:  - Visual Studio 2013 Professional Update 5 is also required (available for download http://www.microsoft.com )
            -  Multibyte MFC Library for Visual Studio 2013 is also required (available for download http://www.microsoft.com )
            -  Visual Studio 2015 is NOT compatible with CA Plex C++ builds. Multiple releases of Visual Studio may be installed
               and run side-by-side on the same PC.