When I was working on a MOC, one part (Hinge Plate 19954) disappeared first. When I tried to undo it, thinking I had accidentally deleted it, the entire model disappeared. With it also the grid. The parts are still listed in the graph. Through the preview window of a camera, the model is still visible. New parts can be added, but are also not displayed.

When I load other models it shows them to me without problems. But as soon as I load this model again, everything disappears again (Model, camera, grid).
I can still export it.

I hope someone can help me with this.