Had a strange error appear last week when using the WCF LOB Adapter for Oracle and spent an hour of my life I will never get back. When attempting to connect to an Oracle DB we kept getting the following error:

ORA-12154: TNS:could not resolve the connect identifier specified

This occurred when we:

1. Tried to generate metadata in our BizTalk project using the Add Generated Items wizard.
2. Tried to generate metadata in a Class Library project using the Add Adapter Service Reference wizard.
3. Connect to an Oracle DB using the Oracle Explorer.

We had all the latest versions/patches of the Oracle client and WCF LOB Adapter (Oh, yeah. Thanks Oracle for packaging patches in easy to consume 1GB downloads...love your work!!)

We could however, connect to Oracle using the Oracle SQL Developer Tool. So we knew something was happening (or not happening inside of VS).

It turns out the issue relates to the install directory of VS2005. In our case it was

C:\Program Files (x86)\...

This triggers an *undocumented feature* in the Oracle Data Provider for .Net (ODP.NET) so that applications with a parenthesis in their (exe) path fail to connect to the server.

The solution was to uninstall VS2005 and reinstall using a different install directory *one that did not have (x86) in it*.

... I know, I did not want to believe it either, but if you want to save yourself time and hair try this solution first.