PROBLEM : While installing Printer driver following error was appearing when USB printer is plugged in.
“the specified port is unknown”
- 1. Open Registry Editor.
- 2. Go to following path
Check if a subkey with the name USB Monitor exists. If not, create it, by right-clicking Monitors and selecting New > Key. Name that key USB Monitor.
Now right-click in the right pane and select New > String Value from the menu. Enter Driver as the name. Double-click driver and enter usbmon.dll as the value.
Now restart your computer and perform the printer installation again. It should resolve the problem.