Hi - I have had this issue. Could be a number of things but try this:
1. Open your file from fresh. If this doesn't work you can always close without saving and you are back where you were.
2. Temporarily remove your libraries. Sometimes random library textures seem to muck things up. So yes you will have buildings with parts missing, but you can restore them later. Re-save your hotlink and try to update. If this works re-install your library parts. If this didn't work try...
3. Go through the motions again with one of your hotlinks but save it as a new name - maybe with 'temp' in the name so you can easily delete it later. Try and insert this in. If this works, your old links may work again (this seems to 'wake up' Archicad), so you can delete that temp one and go back to the way you were.
Conclusion: sometimes Archicad just need to remember what you wanted it to do - I have one project where I need to remind it who is boss like this...
Hope this helps!
