Had a new one recently. A PC running Windows 10, up to date, was taking about 30 minutes to boot. Turning off Fast Startup seems to have fixed it. Reportedly this will do it:
powercfg /hibernate off
but I used a GUI method: Control Panel, Power Options, Choose what the power buttons do, Change settings that are currently unavailable, then unchecked “Turn on fast startup (recommended)”, then Save Changes.
The GUI method is reversible in GUI; the command-line method removed the GUI method from visibility.
Still not sure what the root cause of the situation is, or how to do prevention. But reportedly, a very large proportion of Windows users are in fact hibernating or similar, rather than turning off, and don’t know it, and this can cause Windows updates to fail and other issues related to networking.