I have an appl in VC 6++ that I have ported from my old m/c to VISTA.. On my laptop, I have installed VC++ 6, vs 2008 Exp, VS2008 Std version. I have not been able to successfully compile and link my appl in VS 2008 Exp/VS 2008 Std because of the problem relating to not able to find mfc42d.lib. So, instead I continue to use VC++ 6 for the time being. This was working fine and now for no apparent reason I am getting this error when I build my appln. Linking... mfco42d.lib(MFCO42D.DLL) : error LNK2001: unresolved external symbol MFCO42D_NULL_THUNK_DATA Debug/Process.exe : fatal error LNK1120: 1 unresolved externals Error executing link.exe. Process.exe - 2 error(s), 0 warning(s) So now I have two problems: 1.0 Unable to switch over to VS2008 because of mfc42d.lib not found 2.0 work around with VC++ 6 is now no good because of a new problem Will greatly appreciate help. I know there is a great deal of experience on this in the forum. Many thanks in anticipation.