You either need to find the missing library and load it (or as ling suggested if Archicad library, load the newest library and all the migration libraries if you need to).
Or if you don't have access to the missing library, your only choice is to select all of the missing objects in your model and replace them with an object from a library that you do have loaded.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11