When importing your old forum to your test forum you'll notice that some pm's you've deleted in the past have come back, this is because they are linked from the other user involved in the message's inbox.

You'll find that a lot of these are the "Welcome to our forums" pm's that many of you have enabled; in larger forums you'll have quite the bombardement...

Well, just load up your control panel and run the follwoing SQL Query (Tools -> Database Tools -> SQL Command):
Code
DELETE FROM `forums_PRIVATE_MESSAGE_POSTS` WHERE `POST_BODY` LIKE CONVERT( _utf8 'Welcome to our%' USING latin1 );

DELETE FROM `forums_PRIVATE_MESSAGE_TOPICS` WHERE `TOPIC_SUBJECT` LIKE CONVERT( _utf8 'Welcome to our%' USING latin1 );

Now, you'll want to make sure that you replace "welcome to our" with the subject line of your welcome message. There are two queries because of the two sql tables used.

Since I have used several similar but not exact lines I am using a wildcard search to nuke old pm's.

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