Tenho certeza de que me deparei com esse problema depois que o Acronis Backup & A Restauração 11.5 gravou meu disco em um arquivo .tib.
O sistema de origem e o sistema de destino aparentemente não encontraram C: \ windows \ inf \ usb.inf posteriormente.
Copiei-o do meu netbook e um 'Update Drivers' mais tarde, quando meu teclado wireless logitech k400 funcionou novamente.
Isso parece ter afetado não apenas os receptores unificadores da logitech, mas todos os dispositivos compostos USB.
Meu tablet Android também é afetado, assim como meu receptor do controlador Xbox 360 da Microsoft, já que ele tem dois 360 pads sincronizados, mas meu PowerA Minix360 com fio não é afetado.
Meu microsoft wired keyboard 600 e logitech V220 também não são afetados, já que não são 'USB Composite Device', mas 'USB Human Interface Device'.
Dispositivo Composto USB é usado para agrupar vários Dispositivos filhos em um único dispositivo pai, como dois pontos finais de Dispositivo de Interface Humana USB (Um para teclado, um para mouse) como o Logify Unify Receiver faz.
Um grande obrigado a lucvdv de answers.microsoft.com para descobrir isso :
Some time ago, my system stopped recognizing some, but not all USB devices.
USB ports are fine, it reads the device descriptors but then either says
it's unknown hardware or says it can't find a driver for it.
A second symptom that must have started at the same time is that it
"forgets" all about some USB devices that have always worked fine before,
with the same result: suddenly either "unknown" or "can't find a driver".
Two weeks ago, it was my keyboard.
It still worked when I logged on (it had to, I used it to enter my password).
Immediately after logging on, the found new hardware thing popped up,
after a few seconds it said it failed to install my new hardware, and at
that moment my keyboard stopped working.
Never found a solution, I've been using a PS2 keyboard instead since.
I've tried other USB keyboards, it didn't recognize any of them.
Yesterday, it was the USB hub that's built into my monitor that
suddenly turned into an "unknown device", and nothing I connect
to it is detected anymore.
In an attempt to fix that, I launched the device manager and let it
scan for new hardware.
Result: instead of my USB hub starting to work again, my
Logitech wireless mouse stopped working.
The "USB receiver" is now listed with an exclamation mark,
"drivers for this device are not installed".
It worked fine just a few seconds before.
Right now I'm back to using a wired USB mouse, but I wonder how
long that's going to keep working.
It's not the receiver that's at fault: when I plug it in,
it shows up in device management with the right name and device ID:
USB\VID_046D&PID_C52B&REV_1201 - USB\VID_046D&PID_C52B,
and status "The drivers for this device are not installed. (Code 28)".
Comparing the contents of %SystemRoot%\Inf to another Win7-64 system,
I noticed that file USB.INF was missing.
Copied it over from the other system, started device manager and
re-installed drivers for the non-working devices, and the problem is fixed.
Obrigado pela sua paciência em rastreá-lo, lucvdv!