Are you trying to connect to your board's Linux console through USB? If so, then you will not be able to do so. The micro-USB port was designed to be used with the Arduino IDE for programming and for the IDE's serial monitor.
If you want to connect to the Linux console of your board, you should use an FTDI cable.
Regarding the issue that you mention about the USB not being recognized, have you installed the Galileo's driver?
If you haven’t, you will find it here:
Also, have you seen the following guide?
As I mentioned in my previous post, you won't be able to connect to your Galileo's Linux terminal using its micro-USB port. In order to connect to the board's Linux, you have to use a serial cable. In the following document, you will find which is used with Galileo Gen1 and Gen2:
You will need to use these cables otherwise you won't be able to get the board's IP. You should then follow this guide to connect to Linux: