When I insert SD3 in a project and save it, it loads and works fine. When I open the project later, the midi data and tracks are there but SD3 isn't. If I reinsert SD3 it loads more tracks and if I point the original midi track to the new synth insert, it won't send all of the data to it. I have to start all over from the beginning. What am I doing wrong?
Thank you in advance for any help.
Vince

I'm not able to reproduce that here with X3(e).

Since we are on the subject of SD3,I have a problem also.I assign each drum to its own track,but when I test it it plays on two tracks.And so some of the drums wind up without a track.So if I have kick assigned to track one,its coming out on tracks 1 and 2,when the snare should be on 2,and then the snare is suppose to be on track 2,but its coming out on 3 and 4.I think I have watched all the vids about drum production and none of them say anything about this should happen.I`ve done all the steps that they talk about about,but this is just nuts.

I'm note sure about the issue in the original post, but I think the answer to the hijack  post is that each output in the SD mixer is a numbered stereo pair, not a track number. So Out 1 is outputs 1 (left), 2(right), Out 2 is 3 (left), 4(right), etc. So you need to check the input assignments to your audio tracks and make sure each is set to receive output from only one pair (or one side of each pair for mono tracks).

That might be different too depending if you create mono vs stereo tracks for the outputs at instantiation time.

The OP issue--( see why highjacking is frowned upon) 
I used SD3 with X3 for 2 years and never had that sort of issue. 
All I can think of is it's some sort of demo version?