Bueno, ya hemos comentado hasta el cansancio que se deje de utilizar el IN o NOT IN, por el EXISTS o NOT EXISTS.
Código SQL:
Ver originalSELECT idConver,title,[message],SOURCE,[target],[TIME] FROM [message] AS msg1
WHERE EXISTS (SELECT MAX(id) FROM [message] AS msg2 WHERE msg1.id = msg2.id GROUP BY idConver) ORDER BY TIME DESC