I upgraded a PC with an SSD and had to reinstall twice because windows thought it would be a good Idea just to use the boot partition of the old drive instead of creating a new one on the SSD.

I first noticed that something was weird because I could only delete the system and not the boot partition on the old drive using diskpart. I restarted the machine thinking it would help only for the bios to tell me there was no os on the ssd. I tried booting from the old hdd and sure enough, I landed on the desktop of the ssd install.

To resolve that I had to unplug the other drive, reinstall windows and only then I could boot normally.

60mins of my life wasted as I had just finished installing all the software...