Hi. I have had exactly the same problem, and have to go make a coffee while PD14 goes through saving
chapter thumbnails, then
title thumbnails.
On my current project of about 85 mins length, I've also had it stop at 100% saving, but then hangs. I have to restart PD14, and it sometimes will offer to restart from a temporary file saved earlier (in autosave??). If not, I have to go back to an earlier PDS file.
When this problem reared early in the edit, I started a new PDS save after every few edits, particularly major/tricky ones. I'm using very basic transitions/ fades etc. I'd hate to see what happens when I use some of the complex ones on offer!!
Today I've only managed about 70 various edits, as every third or fourth sends PD14 very sleepy, and sloth-like slow!!
Now trying to burn a disc, but dreadfully slow on accepting each mouse-click/command. Takes 10s of seconds to respond.
I checked my task manager as well, and it gives no hints!!
Hopefully somone can help with what is becoming a common problem.
Editing PC = Win10; i7 6700K; 16GB; SSDs + HDDs.