Turn off your computer and press the Power button for 3 seconds to turn off the scanner, then check the USB cable connection between them to make sure it is secure.
The scanner may not work properly when your computer is in standby mode (Windows) or sleep mode (Mac OS X). Restart Epson Scan and try scanning again.
The scanner may not work properly if you upgrade your operating system but do not reinstall Epson Scan. See Uninstalling Your Scanning Software for instructions on uninstalling Epson Scan. Then follow the instructions on your Start Here sheet to reinstall it.
In the Windows Device Manager, make sure your scanner’s name appears under Imaging devices without a question (?) or an exclamation (!) mark. If the scanner appears with one of these marks or as an Unknown device, uninstall Epson Scan as described in Uninstalling Epson Scan. Then reinstall it by following the instructions on your Start Here sheet.