What have you done for trouble-shooting so far?
Restoring Preferences after making sure all customized presets like Actions, Patterns, Brushes etc. have been saved might be a good starting point:
Are you saving locally or across a network?
I didn't have any custom presets such as those. I think it may have been in part to the dozens of layers I may have had clipped/masked together, but I needed to keep those unmerged to show my work and prove it was my own.
I've attempted to save locally, either directly on my desktop or onto a thumbdrive, both with ample space to save the files.
Have you succeeded yet?
I seem to recall having seen cases where one Layer was indeed the problem – why I can’t tell, either.
So you could try duplicating the image (Image > Duplicate), deleting half the Layers and trying to save.
If it does save undo and delete the other half and try to save again.
If you can determine on bunch of Layers that causes the problem repeat the »process« for those to try and pinpoint the problematic Layer/s.