Quote Originally Posted by Kacto View Post
Donīt know why. I'm using a 12 Mhz oscilator. I checked and re-checked everything on the circuit and seems to be okay.
And again, Use that search button up top, use the keywords 'PIC18F2550' and 'USB'.
There's a nice long thread out that talks all about various reasons why a PC won't recognize a USB item based on a PIC18F2550 (or it's close relatives).