Hello, Environment is Windows 10-64 bit, Delphi Tokyo Patch 3, DOA 4.1.1.0 (at least according to readme.txt file). Scenario. I am using a COM library (AddIn-Express) to build a plug-in for Excel (i.e. a DLL). Everything is working fine and running. I am now wanting to add Oracle connectivity. I have a menu option, which opens a new form. I add an OracleSession component ONLY to this form. This form has a button which does the Oracle processing. For now, there is basically only the following code...

with OracleSession1 do
try
LogonUsername := 'FY19';
LogonPassword := 'FY19';
LogonDatabase := 'orcl';
LogOn;
ShowMessage('Logged on successfully.');
except
on E: EOracleError do
ShowMessage(E.Message);
end;

When I step through the code, the LogOn line is causing an AV with the following... EXCEL.EXE has caused an exception at address... When I click the button, I get the real message... Access Violation in module OraClient12.Dll.

Excel is 64 bit, and my compile option is set to 64 bit. My plugin is working fine with the exception of the newly added OracleSession component. My Delphi Library path is pointing to the 64bit DOA directory. Oracle RDBMS (12.2.0.1.0 64 bit) is located on the same computer. SQLPlus runs fine with the connection string... FY19/FY19@orcl

Any idea what is causing the issue?