HI, In one of my VS 2005 project, I am trying to use CL Command Files(response file). I just could not figure out the correct systax even after reading the document. Really appreciate if somebody could help me out of this issue. In project properties page, Configuration Properties | C/C++ | Command Line(Additional options), I am adding @C:\RESP.TXT File C:\RESP.TXT has /I $(ProjectDir)\include ( I tried /I$(ProjectDir)\include /I"$ (ProjectDir)\include" also) the header file still can NOT be found. However, if I add /I $ (ProjectDir)\include directly to Additional options textbox, that works Thank you for your expert advices,