a 700mb file should open.
To better understand what I am meaning by how much space is free for scratch disk, what percentage of your SDD or HDD is open? You should always have a minimum of 15% open to programs for scratch disk. If you’re at that bare minimum you’ll want to make sure only one program is using that space and that it is dumping its cache when it closes…photoshop is notorious for just eating space and never flushing the cache.
Can you upload the file for someone else to see if they can open the file?
You should always work in iterative saves. I believe Marcus wrote a script that adds an iterative number to the end of a file every time you hit save…but I’m not sure if this was updated to incorporate .zpr file extentions.