I had an old MS Access application (Office 2003) which I upgraded to Access 2013 and needed to configure Oracle instant client to connect to an Oracle 12 db.

The client used IFILE but since the number of users was very small we didn't want to hassle around with the Oracle team which was loaded in work at the time. So I configured the Oracle ODBC connection like this:

1. Open 32bit version of ODBC Data Source Administrator in C:\Windows\SysWOW64\odbcad.exe.

2. Select Oracle in OraClient11g client -> Finish


4. Test connection and Press OK.