Fusion not displaying any media in viewers.

Up until today, my Fusion inside Resolve was working ok. My system isn't exactly all world, so I was trying to find various ways to optimize/cache etc. I must have broke something because now only timelines that were previously created will work under Fusion. Any new timelines, when I click on the Fusion tab, no media is displayed in either viewer. Just a black screen. If I add a node, like color correction the effects can be seen on the edit/color timelines but not in Fusion.

I have uninstalled and wiped Resolve. I've created a new database. I have an simplified export if needed. Hoping someone else has solved this already or perhaps know of a secret button I may have clicked on accident.

Looking forward to more testing. Love the changes and looking forward to cancelling Adobe for good.

Re-install of nvidia drivers seems to have fixed the issue.