I am working on a new doc project that I inherited from a sizzle editor. There is a lot of footage - 10TB in 4K shot on a Canon C300. I am running a brand new iMac 2018 with the below specs. The hard drives are 2 G-Drives probably only about 200/Mbs meant for storage not editing. But I've created a large amount of proxy footage to run it smoothly as the 4K was lagging in playback.
The odd thing is that the program is running slowly in general. Delayed responses to commands, etc. Not unusable but definitely annoying and is going to slow me down. We only have a few weeks to meet our deadline, so want to fix this issue up front/asap.
One thing that keeps bugging me - and I wonder if this is the performance culprit - is that the blue loading bar is always stuck in the bottom right corner close to finished. It gets about 99% done, but never goes away even when project is open for hours. Another issue is that the project doesn't close without FORCE QUIT - I will close the project and then the app doesn't respond until I force it.
I'm having a similar issue - recent inexplicable lag and delay in Premiere Pro... all without any major updates in Premiere Pro or my OS. Similar system configuration as yours. My experience is that it's worse with updated legacy projects. Did you find a workaround?
By legacy you mean projects from an older CC version? If so, that was my situation too.
Sadly I didn't find a work around. I recreated an entirely new project, re-imported and re-synced everything top to bottom, but that suited my circumstance best because I didn't like the way the footage had been synced and organized.
I think there are some clips that it's trying to "load" and just gets stuck on. At one point before I decided to start over, I was just deleting large batches of media and that seemed to fix it. So maybe you can try deleting batches at a time until you find the offending clips, then reimport those.
Let me know if you find any other solution or explanations.