".PDB files cannot be linked due to incompatible versions"

The message ".PDB files cannot be linked due to incompatible versions" can be displayed during builds, even if the .PDB file has just been created by the current compilation (ie, its just not possible that it was built by a different version of the compiler)

The problem is that the mspdbsrv.exe process (which Microsoft uses to create PDB files) does not always terminate after linking.  If you have a mixed environment where you compile and link some modules with VC7.0 and then some with VC8.0, sometimes the 8.0 mspdbsrv.exe process hangs around and interferes with subsequent 7.0 compiles.

Solution: use the Task Manager to terminate it.

Building MFC applications with Visual Studio .NET 2008 Express

For reasons best known to themselves, Microsoft really really don't want you to build traditional MFC-based applications with their new Developer Studio tools - if you want the free stuff, you gotta trade in those testicles and do things with .NET or .nothing.  None of the MFC libraries come in the latest Express (read: free) versions of Developer Studio, nor do such useful tools as RC and MIDL.

However...

You can get RC and MIDL from the Platform SDK.

http://www.microsoft.com/downloads/details.aspx?FamilyId=E6E1C3DF-A74F-4207-8586-711EBE331CDC&displaylang=en

And you can get an old version of the MFC and ATL libraries from the Driver Development Kit.

http://www.microsoft.com/whdc/DevTools/ddk/default.mspx

though in true Microsoft style, those headers contain compile errors.

Line 1034 and 1036 of …\include\mfc42\afxwin1.inl will probably contain the following:
_AFXWIN_INLINE CMenu::operator==(const CMenu& menu) const
{ return ((HMENU) menu) == m_hMenu; }
_AFXWIN_INLINE CMenu::operator!=(const CMenu& menu) const
{ return ((HMENU) menu) != m_hMenu; }

which is incorrect – they generate error 4430. It should be:

_AFXWIN_INLINE BOOL CMenu::operator==(const CMenu& menu) const
{ return ((HMENU) menu) == m_hMenu; }
_AFXWIN_INLINE BOOL CMenu::operator!=(const CMenu& menu) const
{ return ((HMENU) menu) != m_hMenu; }

(And people blame Windows crashes on "bad drivers" - how hard can it be to write a driver when the DDK has such blatant errors - they literally cannot have tried to compile with these headers before shipping them)

Sadly, whats discussed here only works up to VC8.0 - at 9.0 the ATL changes are too drastic, as I found out the hard way.  If you want to use MFC or ATL, you can't use Visual Studio 2008 Express.