Changes have been made, in the 2016 version, to the way in which you can record MONO tracks.

Recording using external synths via the soundcard has been changed slightly. You designate your track as MONO and record to it. Now Blocks are entered on the track to which you are recording showing that data is being sampled. The setting in Preferences Audio Panel "Input for MONO Tracks" can be the default of L & R, or changed to Left or Right only. When the recording is accepted and where the MONO options is Left or Right., MONO data is pasted directly to the track. If L & R ( in effect Stereo) is selected then an Option is offered asking what you want to do with the spare Mono data - to ignore or paste to anther blank track.

The right click menu in the Main Tracks Window provides two options for tracks to be recorded by rendering via VSTi/DXi plugins.

1 Auto Convert individual Midi track to Wave file

2 Auto Convert individual Midi track to Audio Track

Taking option 2 first - this option never gave you MONO tracks previously and has not been changed.

Option 1 worked in previous versions of RB where a stereo was always created and saved outside the Seq file into the Song Folder. These wave files acted as a security measure and were Imported into the seq file to the required track. If the track was designated stereo audio then the data was pasted immediately. If the track was designated MIDI or MONO audio, then a Message Panel would be displayed "File is stereo Ok to import instead of Mono track. Yes or No. The next Panel offered the options to import to Mono or Split the Stereo into twin tracks.

This method has worked well in the past BUT has, for some reason, been removed from the program. There appears now to be no way to obtain MONO tracks using this Option.

You can use the Tracks Menu > Split a stereo track into 2 Mono tracks. This command allows you examine each channel and decide which to use. After selection, the unwanted tracks can be deleted.

In my view, the method which has been used for many years to record directly via a soundcard, should be used for the two render options. Use the track designation and Preferences Mono tracks setting to control the input of the recorded tracks.

The easiest method, would be to replace the previous options when importing wave files to a seq file.