I use the ODBC Template, almost as is, to install ODBC 3.0. However, I
have a problem when I upgrade a machine that has ODBC 2.5 installed, and
has an application (or NT service) that is using ODBC. As I cannot
readily detect which application is using ODBC, I have no way of telling
the user to close that application at Setup, and I have the following

The ODBC installation reports that the "ODBC Resource DLL (odbcint.dll)
is a different version than the ODBC setup DLL (odbccp32.dll).". It then
warns you that this is a severe error, and requires ODBC to be
reinstalled. This will frighten a lot of users.

I presume that the ODBCINT.DLL was in use, and so was marked for upgrade
at a reboot, but that the odbccp32.dll was installed correctly, and that
when I come to make my ODBC calls in the ODBC template, that I get all
the errors.