I've recently upgraded an application from Oracle 9i client to Oracle 10g client. The application is written entirely in C++ and uses the Oracle Objects for OLE (OO4O) library. The development environment that I'm using is MS Visual C++ 2005. The following problem occurs only when debugging the application. The call to OStartup returns a value of 1 instead of 0. Even though this may be a failure condition, when I create session, database and dynaset objects, these all function correctly. Upon exit after the call to OShutdown, the program generates an access violation, though there is no debugging or source information available. I suspect that some DEBUG runtime DLL is causing the issue, but it's unclear which one. I have a sample console application that demonstrates the problem, if anyone requires some code to try to duplicate the problem. My main question though is what does it mean when OStartup returns a value of 1? Thanks.