When attempting to connect to an Oracle database from an ArcGIS application, the following error occurs:
"Client software failed to load. Be sure the database client software is installed and configured correctly."
This error may occur for the following reasons:
To solve the issue, ensure that the Oracle client is installed and that the bit-level of the client matches the bit-level of the connecting application.
If both the 32-bit client and the 64-bit clients are installed on the same machine, the 64-bit client must be listed first in the PATH environmental variable for a Windows operating system.