Well this is a new one. I've been working on a project slowly with a mate over the last few months, and have had no issues when exporting the mix to listen to in various environments etc. Over the last few days however, when I export the mix to either wave or mp3, all of the midi based instruments are all over the place! What the???
 
I have 1 instance of Addictive Drums, 1 True Pianos, 3 Dimension Pros. They all render out of time with the audio! Any clues would be much appreciated - this has only just started happening over the last few days. Is there a check-box or a setting I've accidentally enabled/disabled in this project? Or is this a nasty gemlin! 
 
Any suggestions/help much appreciated, I'm using Platinum Foxboro. 
 
P.S I've just noticed all the midi stuff is in time with itself but way late with the audio. I've tried fiddling with export options but with no luck. Also to note, none of the midi instruments tracks have been frozen. Maybe i'll try that next and re-export?? 
 
UPDATE: So for some reason exporting now works fine. I didn't freeze any synths or try any new settings. I just tried the same old export audio process I've done hundreds of times, and this time it all worked fine!!  I've had a few odd things happen on this project so I guess I'm leaning towards gremlins unfortunately!  

Huh....    Did you leave any food near your DAW after midnight?   
 

I used to get this with Vienna Symphonic Library.  It had it's own buffer setting that I had to disable (set to 0).  It seemed to be sporadic.  One day it would get out of sync and the next day it would be behind by a few milliseconds.

I don't know if this will help you in any way, but it may be worth looking into.

Huh.... Did you leave any food near your DAW after midnight?

 
Ha ha, yeah all the food was gone and the project worked! I should have known, the PC was just hungry!
 

I used to get this with Vienna Symphonic Library. It had it's own buffer setting that I had to disable (set to 0). It seemed to be sporadic. One day it would get out of sync and the next day it would be behind by a few milliseconds.

I don't know if this will help you in any way, but it may be worth looking into.

 
Yeah you know my gut feeling is that there was some weird buffer thing going on also. The weird part however was that all the midi instruments were in time with themselves, but out of time with the audio!  I was wondering whether there was a buffer setting on the project or in preferences that caused the issue. I'm not a massive 'settings fiddler' so there could be adjustments needed to be made, however I've generally not had issues with my setup for a long time. 
 
 

I was having timing problems with some softsynths a while ago. Surprisingly adjusting the midi buffer to a lower value cured it. I can't remember what settings I was using though.
 

I was having timing problems with some softsynths a while ago. Surprisingly adjusting the midi buffer to a lower value cured it. I can't remember what settings I was using though.

 
Thanks Kev. I found a setting in the config file which was something like ignore buffer settings on export, cant recall the exact name of it off hand, but enabling that made no difference - it sounded like the midi exported at a different sample rate. Anyway, touch wood, it has been exporting fine over the last few days - weird.