Blank screen when starting DaVinci 17

I upgraded to ver 17 and installed the Speed Editor at the same time. At the beginning all worked fine, but then the following problem appears:
I start Resolve, see the Project Manager, chose a project (or New Project) and then I just see a blank screen with the menu bar above, but nothing else. Most of the items under the menu "DaVinci Resolve" are greyed out, including "Preferences" and "Quit DaVinci Resolve". Sometimes they reveal after a while, but the screen remain blank. I tried "Switch to Page" in "Workspace", but no result.
After a couple of restarts, plugging and un-plugging a USB-C cable on the Speed Editior, the program finally starts, but prior to writing this post, I started and restarted the program 7 times, but I have still not managed to get it to work as it should.
My configuration is MacBook Pro 15 inch 2018, i7 2,6GHz 6-Core, 32GB DDR4, Radeon Pro 560X 4GB, macOS Big Sur 11.3.1. I'm using an external monitor, LG UltraFine 27'', with the lid on the MacBook closed.

[Peter Chamberlain]

moved to resolve forum

Problem solved. It appears that some remaining of plug-in apps that I deleted earlier prevented the program from starting. Once I cleaned these away, Resolve works perfect.