Windows 10 extremely slow on startup

A lot if not nearly all people with high spec machines experiencing low W10. Not logical unless there is something wrong with the installing of the OS.

Step 1: Backup your data, and do that now and first before the next steps.
Step 2: how many different profiles are on the machine? How big is the initial load? ALT-X -->System -->Advanced System Settings --> User Profiles. Also is there maybe a huge ISO sitting on your desktop? Remember your desktop is loaded partially into memory.
Step 3: Start your machine, be it painfully slow, start msconfig and disable everything (you can do a Diagnostic Startup as well). Also stop all services in MsConfig Services tab. Click Startup Tab and disable everything there. - Reboot
Step4: After reboot some of your settings might be off or look completely different, depending on if you are running any services that perform things like continuous scanning like some antivirus programs do. Why it only happened two weeks after, maybe because it was set to perform a full system scan on a schedule and you have a lot of zip files - it needs to unpack them and generate a signature.... Your bootup should now be faster, if not then there are bigger problems.
Step 5: SSD - make sure hibernation and page file are off, also make sure your disk is trimmed optimally.
Step 6: Only if the bootup times have returned to acceptable values start enabling the services and startup items, reboot EACH time after you enable one step to see if you can identify the matter. It could be as silly as a corrupted config or definition file (antivirus or even a desktop conf file).
Step 7: There can be a problem with one of the memory sims, only to show up if you load up more than 4GB.
Step 8: As you notice it is time consuming to perform these steps, so be patient, take lots of time (no rushing). Also it can frustrating too if people are waiting to use the laptop.... believe me I know.