Years ago, there was a frequent problem that people would have certain drivers installed that caused all serial ports to be opened, that would cause the error you're experiencing. I haven't heard anyone report this on Windows for a very long time. Here's the relevant entry in the (extremely outdated) official troubleshooting guide:
Check that you're not running any programs that scan all serial ports, like USB Cellular Wifi Dongle software (e.g. from Sprint or Verizon), PDA sync applications, Bluetooth-USB drivers (e.g. BlueSoleil), virtual daemon tools, etc.