Opening project gives me constant beach ball..?

I have a project that requires a lot of green screen work. And I'm just having problem after problem with Resolve.
I open a project that was just a simple green screen key pull. I rendered out a B&W sequence. Now I'm bringing the sequence into Resolve/Fusion so I can reuse the matte because I have to fill a couple holes in the matte,
When I open the project, I just get the infamous spinning beach ball on my Mac. I'm on an iMac Pro. Not exactly little Johnny's laptop. I cleared the cache. Yet, when I want to create a new timeline, I just keep getting the spinning beach ball popping up every two seconds. Preventing me from literally doing anything. I've never had this kind of performance issue before with any other app. My Fusion dongle isn't working...why, I don't know. So, I have to work with Resolve/Fusion in the meantime.
What's with the spinning beach ball? Anyone have any ideas to resolve this?
Thanks.
I open a project that was just a simple green screen key pull. I rendered out a B&W sequence. Now I'm bringing the sequence into Resolve/Fusion so I can reuse the matte because I have to fill a couple holes in the matte,
When I open the project, I just get the infamous spinning beach ball on my Mac. I'm on an iMac Pro. Not exactly little Johnny's laptop. I cleared the cache. Yet, when I want to create a new timeline, I just keep getting the spinning beach ball popping up every two seconds. Preventing me from literally doing anything. I've never had this kind of performance issue before with any other app. My Fusion dongle isn't working...why, I don't know. So, I have to work with Resolve/Fusion in the meantime.
What's with the spinning beach ball? Anyone have any ideas to resolve this?
Thanks.