Once Oracle 18.x/19.x is installed the customer must follow the instructions here: Registering Oracle drivers for Power BI Desktop Administrators can still place ODP.NET in the GAC and add the configuration section handler and DbProviderFactory information to nfig manually if they wish to override ODP.NET settings for individual applications.' 'Machine-wide configuration is no longer supported beginning with ODAC 18c. You must choose a windows installer version since xcopy version does not work with Power BI Desktop.
To install the 64-bit ODAC software, go to 64-bit Oracle Data Access Components (12.1.0.2.4) or choose a version you prefer. To install the 32-bit ODAC software, go to 32-bit Oracle Data Access Components (12.1.0.2.4) or choose a version you prefer. It also depends on your version of Oracle server. The Oracle client software you use depends on which version of Power BI Desktop you've installed: 32-bit or 64-bit. To connect to an Oracle database with Power BI Desktop, the correct Oracle client software must be installed on the computer running Power BI Desktop.
