I ALWAYS copy the vm folder to a temp file if I am not sure or not comfortable with what the results may produce.

I would copy the hole VM to a tempvm and then run it.

If it does screw things up, you just copy the files back and your back where you started.

If it cleans it up and you lose a mailbox, you can rebuild it and then copy the messages and greeting back into the M dir. for that box and run message audit for it.

Be careful when running message audit. It will bring ALL messages back as saved.

Good luck.