When attempting to Build Output getting the following error.

OLE IDispatch exception code 0 from ListImages: Invalid key.. System Error # 1429

How do I fix?

Not sure without more context. ListImages is related to the icon collection for the images that are used for topic types. Either there's some invalid name involved or a file is locked and inaccessible.

FWIW, I would think this would fail before building the project...

+++ Rick ---

Thanks Rick -used recovery file and worked. Renamed recovery file to actual file. Glad the recovery exist. Enjoy the holiday weekend

Ah good. If that was the problem then most likely an invalid category slipped into a topic...

+++ Rick ---