I have the document organised in layers, but that helps only during the work since not so many objects have to be diplayed/handled. Good thing to do if you have such big files. However, I do not think that it will have any influence on saving the document, since all information (including all layers whether activ or not) will be saved. Correct me, if I am mistaken. Sentinal, what config do you have and could you observe if it happened only above a certain file size?