HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\Maintenance If you want to give this peculiar fix a try, This is especially true for PC and Laptops with Dual graphics cards. With some of the tests that I attempted, Automatic Maintenance in Windows 10 leads issues resulting in the dreaded spinning dots for ages. But for users facing the slow spinning dots when restarting or booting up Windows 10, this might just be the fix that you may be searching for.
The reason being this has not been widely reported to be an issue. This Windows 10 slow startup fix might be unheard of for most users.