Error optimizing queries: "ORA-01026: Multiple buffer Size > 4000" (4223832)

Error when optimizing queries: "ORA-01026: Multiple buffer Size > 4000".

The issue started since SQL Optimizer was upgraded to version 8.6 or 8.7

RESOLUTION 1:
Perform a complete uninstall and reinstall of SQL Optimizer. Ensure to remove all SQL Optimizer folders:

C:\Documents and Settings\user name\Application Data\Quest Software\Quest SQL Optimizer for Oracle
C:\Program Files\Quest Software\Quest SQL Optimizer for Oracle
C:\Program Files\Quest Software\Quest SQL Optimizer for Oracle Common

Reinstall SQL Optimizer using standalone SQL Optimizer MSI installer.

RESOLUTION 2:
Please ensure that the NLS_LANG parameter is set in accordance with the Windows locale.

If there is an NLS_LANG parameter in the Windows Environment variable list, this will over-ride any configuration set in the registry entry for the Oracle client. The NLS_LANG parameter in the registry will also need to be set in accordingly with the Windows locale setting.

If there are multiple clients please also ensure that the relevant Oracle client is selected in the connection window in SQL Optimizer.