Here’s a useful, practical guide to finding, installing, and troubleshooting the driver on Windows 10 . Important clarification: The model “UB-U03II” appears to be a variation of the common Epson UB-U03 or UB-U03III (a USB-to-Serial converter box used with EPOS printers). If “U03II” is a specific variant, the driver solution is the same as for the standard UB-U03. 1. Correct Driver to Use The UB-U03 is not a printer—it’s an interface converter. Windows 10 will typically recognize it as a USB Serial Port . You need the Epson UB-Series driver (Virtual COM Port driver).