Hi, please refer to this article for information regarding the form instructions that ProConnect uses to determine if the Schedule M-3 should generate or not.  Generating or Suppressing Schedule M-3 in ProConnect.  The items listed on the article for each module are the only things governing whether or not the software will generate the M3 automatically, or you can also "force" it to generate.  For information as to what information you are required to enter based upon your client's situation, please refer to the IRS form instructions.