Okay, now I have tried re-doing the "initialise root resonances" and it does not make a difference. The last spin-systems are still not exported. Also I have tried to make sense of the way the first spin-systems are being exported. So most C-1 -atoms are in a new spin-system and most of them are being exported (not all), but some are not in a new spin-system and some of these are exported and others are not. And adding them to a new spin-system or removing them from the spin-system makes no difference in what is being exported. Also some of the C-atoms are not exported and here there is also no obvious pattern as to why. Some of these have their C-atoms assigned to CO, CA or CB of that spin-system while others does not and again changing it makes no difference in the exported files.