Toad For Oracle User Manual

This has been happening since I upgraded the Oracle Client to Oracle 12c from 11g. Here is what I have done so far to try to resolve it based on internet research: I checked the path variable, it's currently set to C:\xyz\Oracle\ora12.1\client_2\bin, and there is an Oracle installation at this path. Toad for Oracle, No valid Oracle clients ... ................
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