Toad for Data Analysts connection error: ORA-12154: TNS: could not resolve the connect identifier specified and the Database Names drop-down list in the TDA login screen is empty or blank. Direct Tab works, but the TNS Tab does not work.
TDA and Oracle Client was freshly installed. Oracle Instant Client does not work either. All connections issues troubleshooting check list were done, but the error or blank Database Names drop-down list still persists.
What else can I check on this?
Ensure that your "tnsnames.ora" extension is indeed a .ora file extension type. Go to Windows Explorer | Tools | Folder Options | View Tab | un-check "Hide extensions for known file types" | click Apply and OK. Then re-verify that the tnsnames.ora file does not have any other file extension in it i.e. tnsnames.ora.txt.
