Are we talking about the same model on 2 different computers?

If the model has changed, maybe you introduced a faulty model that blocks rendering.
Solution:
1 - delete half the models, try to render.
2 - if it works. undo deletion and delete the other half of the models
3 - if it works, the problem doesn't lie in the models, but in the size of the file, or there is a compatibilty problem with your computer/software?
4 - if it doesn't work - again delete half of the models, and repeat until you find the faulty model