Boot suddenly takes, sometimes, minutes, from seconds, to end with SSD

Hi guys, let me explain what happens when I turn on the pc:

1. Everything turns on: MB, GC, fans, LEDs, all I/O devices.
2. The classic BIOS window (press F2 to access BIOS..) appears and it lasts, correctly, around 3 seconds
3. The message "press F2 to.." is replaced by a loading wheel and all I/O devices are shut down (LEDs turn off) but not the MB, GC, fans and PC's LEDs
4. This goes on for more than one minute until all I/O devices turne back on and, immediately after, Windows 10 log in happens and everything works fine

Additional informations:

1. This started some months ago and I can't identify the event (such as a new device) that might have caused the issue to appear
2. It doesn't happen all the times (90%+ maybe?). I can't 100% force it to boot properly but, when it does, it only takes 5-10 seconds
3. During my tests to find the cause, I tried a lot of scenarios by unplugging the diffent I/O devices but I can't find a pattern. I'm only sure that it is always happens if I restart the pc
4. I thought it could have been my usb ports not shutting down when my pc does, but I changed it via BIOS and the problem is still present
5. I tried some WPR analysis regarding the boot phase and everything seems ok, only the postboot lasts 50 seconds (the previous phases only a couple of seconds each). Looking at the postboot's details, it regards the auto run processes and I'm sure the 1+ minutes of loading happens before. Basically this "black out" isn't apparently recorded at all (or I can't find it)
6. All my drivers are up to date and there isn't a singol problem when the PC is turned on
7. MB is an ASUS z170, GC is an NVIDIA 1050ti, processor is an i5-6600K, only one SSD is connected and, finally, the machine is an ordinary home pc.
8. SO, as I already said, is Windows 10 pro 64bit

Is there something that I can try?

Based on your statement "always happens if I restart the pc",I'd say that you are experiencing Fast Startup after a shutdown..
Windows 10, by default, has a mode called Fast Startup that is a hibernate like mode used if you shut down your PC. It allows allows a faster start. However, if you restart the PC, it goes through a full boot that takes much more time.

pbcopter said:

Based on your statement "always happens if I restart the pc",I'd say that you are experiencing Fast Startup after a shutdown..
Windows 10, by default, has a mode called Fast Startup that is a hibernate like mode used if you shut down your PC. It allows allows a faster start. However, if you restart the PC, it goes through a full boot that takes much more time.

I already tried to change this option and it isn't the solution.

I had a different suggestion that it might be a check for hardware problems, something like a component not correctly plugged in. I don't think this is it because I cleaned my pc not so long ago and I also can't see any performance issue even while running heavy softwares.

But, this made me try something else. I tried to start the pc without any I/O devices connected (headset, mouse, keyboard..) and the boot went on without any delay. I then tried to connect them one by one in order to find the culprit but I ended up with all of them connected and no problem whatsoever. This made no sense to me and I decided to try a restart and the problem was there again.

Later on I tried again the unplug everything method and this time the boot had its delay from the beginning, in the end I can't find a clear pattern

Check all partitions on all disks and ensure you only have one partition marked Active on the main boot drive. You an use Minitool Partition Wizard to check this. Set any unneeded active partitions to inactive, Having more than one active partition can confuse the boot process. I would also remove the CMOS battery then load the BIOS defaults. Check your BIOS is up to ate.

What is this windows boot manager thing? I installed an a new m.2 drive and this item was also in my boot load order. Also my load time sometime slower. Maybe thats it? (Sorry quick scanned all the post)