the operating system or app does not recognize a connected USB device
Nothing useful can be tested until the device or browser path is visible. Start with connection, power, permission and OS recognition before app settings.
Do not jump to the most invasive fix
Do not install unofficial driver packs or firmware from download sites just because the device is missing.
Retest the same condition
The first milestone is simple detection. Only after the device appears should you troubleshoot signal quality or app behavior.
Rule out the simple causes
- 1
Reconnect the device and try a known-good port/cable appropriate to the device.
- 2
Check whether it appears in the OS device manager/system information.
- 3
For devices supported by normal browser APIs, run the matching DeviceOK camera/audio/gamepad/input test.
Work through the problem in order
- 1
If the device is missing everywhere, inspect power, cable, hub, port, and device-specific driver/firmware from the official vendor.
- 2
If it works on another port/computer, focus on the original port/hub/OS path.
- 3
WebUSB availability is separate and should not be used as the sole recognition test.
If the matching DeviceOK test succeeds, prioritize the affected app, browser policy, operating-system setting, or configuration before assuming complete hardware failure.
If the same capability also fails in DeviceOK and another trusted diagnostic path, broaden the investigation to connection, operating-system/device state, official driver or firmware support, and finally hardware.