Hi Andrew, I fear you prepared too carefully: the FC does not recognize HBa/HBb type naming because it's not in use anywhere except 'inside' CCPN as it were. At this point your assignments should be in CCPN but are not linked to the atoms - you can try to rerun linkResonances (from Process->Run linkresonances, say No to the question asking you to run it automatically, after a couple of other questions you should get popups asking you what the HBb/HBa names mean in terms of atom assignment - link them to the HB2/HB3 option in the atom names dropdown, same for all other ones). Hope that helps, Wim