I have been having a curious startup problem as well that seems similar. Sketchup is taking more than 10-15 minutes to open medium sized files that normally start in 30 seconds. I have older computers that will open them “normally” but my new laptop will not. First I tried disabling all my extensions and for a bit that seemed to work… then it didn’t. I thought that was curious so then updated windows and NVIDIA drivers. That worked for a day. I booted up this am and back to ridiculous load times. I can’t find a pattern or logic to it. I feel like it has to do with Windows as my older / slower machines (that are not as updated) open things just fine. I know windows meddles when it updates but I am not sure what to look at. I have the NVIDIA graphics card set to be used over the Intel Graphics.
This machine opened them fine as well until this started happening about a month ago. Any ideas of where to look would be appreciated.
SU 2018 Windows 10 64bit nVidia GeForce Pascal GTX1070 Max-Q 8GB GDDR5 DX12
CPU Coffee Lake 8th Gen:8th Gen Intel Coffee Lake Core i7-8750H, 2.6~4.1GHz
Update: I discovered in my task manager the core that is being used for skp is completely maxed out while opening the file despite running at a higher clock speed than other machines opening the same file. The other machines do not max out the core while opening like this one does.