Windows not booting correctly (sometimes/every second time?)

[Ombiax]

Sooo, I could need some help.
About every second time I start my computer it shows the message "insert boot device(?) and..." or something like that. You should know what I mean, the standard. It's just that I don't know how to get rid of it. I don'T think (?) I have a second windows boot on one of my hard drives anymore, but it could still be. Don't know how to look after that though, so I could need some help there. If it's not that, I would be clueless from there on. And yea, after every single time botting the pc it wants to scan my C: or I can press any key to skip that. Normally, when it doesn't start up, I just hook up another keyboard (using a 60% currently) and spam pressing F8 and then selecting my SSD.
I am running a "gaming machine". i5 3570k (overclocked), GTX 1060 6GB, 16GB RAM, Windows 10 Pro 64-bit

[Slayerking92]

Cloned OS?

 

[Ombiax]

On 9/13/2021 at 8:22 PM, Slayerking92 said:

Cloned OS?

 

Maybe. But how do I check it or even get rid of it?