Signature collision in Windows 11, why?

I'm running into a problem in Windows 11 I can't figure out, maybe someone has ideas... I have a hard drive connected to my motherboard in a hot swap SATA rack called Project 20 . This is my work drive. I occasionally plug in a HDD to make a mirror backup with FreeFileSync in a USB SATA dock to a drive called Project 20 BCK . It detects new files and copy those. I usually plug USB drive with PC running, making the copy and eject. But this time i have plugged in the drive while OS was shut down. Booted with both drives connected and this is what happened: I see Project 20 HDD but USB drive is b

Question by sp4rk on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.