You need to let us know what type of computer you are running Cubase on because you need to download and install the driver, then select it within Cubase. Otherwise the computer doesn't know what's connected. Let us know.

A Mac - didn't realize I needed a driver for the motif ... There's no mention of it in the cubase set up process. Where can I download the motif driver for cubase?

On a separate note after being unsuccessful syncing the motif I tried to use the audio feature in cubase to record a guitar. I was able to get the guitar to record (can see that the signal is picking up and recording) but am unable to play it back/ hear it from cubase. Can you use the Mac's speaker or headphones into the Mac to listen to what's recorded in cubase?

Thank you

A Mac - didn't realize I needed a driver for the motif ... There's no mention of it in the cubase set up process. Where can I download the motif driver for cubase?

No it's not, but it is mentioned in your Motif XF Owner's Manual, in the chapter: "Using a connected computer" page 56. Since you just got your Motif XF we assume you got it "Fully Loaded"... This includes the FW Expansion Board. The FW16E lets you communicate MIDI and Audio to and from the computer.

If you are connecting via USB, then you will be able to record MIDI (only) to your computer

The Official Yamaha Download site:

http://download.yamaha.com

Connect the FW16E to a FireWire port on your Mac. If it has Thunderbolt you'll need a Thunderbolt to FW adapter.
Current FW driver for Mac is Yamaha Steinberg FW driver version 1.7.4

If you are just recording MIDI then. download and install the appropriate YAMAHA USB-MIDI Driver for your computer's operating system

On a separate note after being unsuccessful syncing the motif I tried to use the audio feature in cubase to record a guitar. I was able to get the guitar to record (can see that the signal is picking up and recording) but am unable to play it back/ hear it from cubase. Can you use the Mac's speaker or headphones into the Mac to listen to what's recorded in cubase?

Not a separate note, same note and a part of the same tune: download and install the driver - audio from the computer will use the audio outputs of your Motif XF

I'm confused - I thought / understood from the store where I bought the motif that it could sync directly via midi with a usb cable to the Mac and cubase. Salesman didn't say I needed any further hardware (like the fw16e). I did get a focusrite for guitar and mic audio inputs to the Mac. The fw16e is required to have the motif talk to cubase?
Thanks

The fw16e is required to have the motif talk to cubase?

No, but if you just purchased a Motif XF (between Oct 31, 2015 - March 31, 2016) you are eligible for the "Fully Loaded" promotional package which includes the FW16E (plus a bunch of other stuff - FREE)! The FW16E is not required for the Motif XF to talk to Cubase. You can talk to Cubase via a USB cable... But as I mentioned that "talk" will be MIDI only....

If you wish to "talk" (record) audio to Cubase you will need an audio interface. The FW16E is not only an audio interface for the Motif XF, it allows you to plug in your guitar or a microphone and record that to your computer, as well. It is a 16-in/6-out audio interface for your computer that installs in the Motif XF. It handles both MIDI and audio communication, and turns the Motuf XF into the most powerful music production system you can buy in a single keyboard!

I'm surprised the salesperson did not mention the promotion.... Please see the following promotion that runs through March 31st, 2016: (at least here in the USA - promotional opportunities can vary by location).

Motif XF Fully Loaded

Free stuff!!! Plus discount coupons for additional software items, etc...

Here is a tutorial for MIDI-only setup via USB:
Motif XF USB-MIDI Setup (Macintosh)

Here is a tutorial for FireWire setup:
Motif XF FireWire Setup (Macintosh)