When launching SQL Optimizer, an "ORA-12154: TNS:could not resolve service name" error message is received.
If error occurs only when running Optimizer from within Toad, then machine does not have the specific Microsoft XML Parser TOAD requires to launch SQL Tuning.
RESOLUTION 1:
Download and install this Microsoft XML Parser. You can download the XML Parser from:
http://www.microsoft.com/downloads/details.aspx?FamilyID=3144b72b-b4f2-46da-b4b6-c5d7485f2b42&displaylang=en.
RESOLUTION 2:
If error message also occurs when running Optimizer as stand-alone, then verify the System Path variable of machine:
1. Start | Control Panel | System
2. Advanced Tab | Environment Variables
3. Under System Variables list, scroll down to Path and select Edit
4. Move the BIN folder of the Oracle Home to the first path listed on the list of paths
RESOLUTION 3:
Rename the NLS_LANG key in Local Machine/Software/Oracle/ in Windows registry. Check with your DBA before making this change.
When trying to connect, verify you have selected the correct client in the connection window.
