FM12: Crashes when opening files and numbering pages

My FM12 is running on a VM with Windows 7 and 6Gb of Memory - it's a pretty large book, 750+ pages. When I get more than 700 files open, it crashes. Then it will crash while numbering.

What should be a straight forward publishing of the book is taking two days due to crashes. I have to save the files after I open a batch and apply numbering or I lose the entire book.

Also, when I select a few files in a folder, FM opens the entire folder of files which is really weird.

It's version 12.0.2.89