Check the order of your hierarchy is correct, and that nothing refers to anything else in the scene until after it has been calculated.
But this is really what Save Incremental is for - ALWAYS save incremental versions of files, so that when one craps out on you, you have the previous, separate file to go back to. Without reference to the file, or much clue what the setups are, or without knowing even which version you are working in it is difficult to advise specifically ! But there is no function I am aware of that will repair a broken or corrupted save file.
CBR