On some Brother duplex printers, the FinePrint duplex setting does not work. This can be corrected as follows:
1. Right-click the Brother printer icon in the Windows printers folder.
2. Select “Printing preferences”.
3. Navigate to the Advanced tab and set it as shown below.
This should fix the problem.
Note: This fix applies to automatic duplex printers only. If your printer driver does not have this setting, it is likely that the FinePrint will not be able to control the duplexing for the printer.