That message indicates an error in the model’s geometry data management. It is seen most often when you have imported a model from the 3D Warehouse and that model either contains a flaw or collides with prior contents in your model to produce the flaw - though it can also happen at random without import. In effect, it is a confession that there is a bug in the geometry manager, as no entity should ever get id 0.
The message is a bit confusing because it tells you the issue can’t be fixed and then that the offending entity has been destroyed. What it means is that the geometry manager can’t find any way to determine what the offending entity was meant to be, so the only fix is to erase it. Most of the time this leaves the model perfectly fine so you can save it and get on with work. In the rare cases where it damages the model, you can revert to a previous version if you follow the good practice of saving frequently.
Thank you very much for your speedy and reassuring reply. I suspected as much and deleted all imported models, but still had the same message. Anyway as long as it is saving I’m reassured, I’ve been working on this all day and the thought of losing everything…well I can’t even think that, the computer would probably end up being launched from my window!
Deleted components still reside in your file, components in the in model collection, as well as used styles and materials( both in their own ‘in model’ collections) you can purge unused components, materials and styles by right clicking the little blue ‘details’ button in their trays and select ‘purge unused’
Or you can purge all three ‘in model’ collections in Window>Model Info>Statistics >purge model