“Plug n play” is more a goal than an achievement... particularly, when dealing with computers and musical gear. If you ensure a certain minimum of settings in each, it will ‘seem’ like it is “plug n play” but if you miss one of the items and you’ll wind up scratching your head.

First, you want to ensure that your computer ‘sees’ the MX. That you can do by:
__ setting the MX to MIDI I/O = USB
__ navigating in your computer to view the Driver control panel and verify MIDI communication.

The driver version, computer type, and computer operating system must all work together and be compatible for anything like “plug n play” being achieved.
The USB connection to the computer needs to be verified — it should be direct, if at all possible. Depending on what type of computer you are using, you may need to use specific adapters as recommended by your computer type.

All of these need to be verified. You don’t say what type of computer, what driver version number, but verify you have the ones required for your gear. Then, verify that your computer is ‘seeing’ the MX.

Thanks so much for your help. Really have come to rely on this forum when I hit a proverbial wall....it’s a windows laptop running current OS. The usb connection is direct (cable from MX to USB port on laptop) and I set the MX to usb...same messages though.

Anything else I could try?

Thanks again
TM

On your Windows computer:
With the MX powered On and connected to the computer...
Go to START > scroll down to “Y” — find “Yamaha Steinberg USB Driver” > Control Panel

The DRIVER Control Panel will appear with three tabs (if it is setup properly) it will identify the “Model”, set “ASIO“ buffer size, and “About” the driver version.

Tell us what your computer reports on each of the three tabs...

sorry for the delay, was away from the computer until yesterday....
I am able to get a connection now.
those three tabs say:
Sample Rate: 44.1
ASIO: buffer size: 512 samples
About: version 2.0.3

so my problem now is actually doing anything w/ the software. I'd like to gather up the various voice/performance things I've downloaded (BOMB etc) and make a "best of" 128 performance set. but the MX does not show up in the computer as a USB device even tho it's connected...
thanks in advance for any/all advice.
TM

The MX is showing up connected to the computer. Odd that one of your tabs says 44.1 and not the name of the synth. Are you sure?
Anyway, I’m pretty sure the tab says “MX49” and that the Sample Rate is 44.1kHz.

That is “showing up” in your computer as a musical device. Your computer isn’t NOT musical... everything that it does musical is assisted by Drivers or Software that speak directly to your musical gear. It is the Driver that identifies what is connected to the computer. The computer can recognize a USB stick if you connect it (because it has been ‘taught’ to recognize it as a storage device). Your computer can write to a USB stick and with the help of specific computer software it can write a file that your synth can read. There are standard file types developed for musical gear.

Software like the Melas Tools can also address the synthesizer using MIDI BULK DUMP protocol. So you will ‘see’ the MX in two places (only):
In the Yamaha Steinberg USB Driver > Control Panel, and through various specific Software programs that are musical and can speak the language of musical communication.

You have the John Melas Tools for MX, you want to use it to assemble the MX Voices and Performances.
Once you have copied those programs you want to assemble into your personal “best of...” Bank, save it. You can:
— Bulk Dump it from the Editors into the MX via your USB-MIDI connection.

OK, thanks very much...will try that today.

side note: I'm super impressed with the way the MX is programmed. it does essentialize many many elements of the Motif line into a user-friendly and approachable package. been using the FM Essentials via iPad and it's great too.

I get that we're at the end of the Motif line and now all the development/R&B is into Montage series. still I think there's a market for an "MX Pro" type device -- my wish list would be 73 keys w/ the keybed from the CP series. an additional user bank for 127 performances (maybe voices too?), a phrase looper with 10 minutes of time and unlimited overdubs (with a way to save the results internally, as part of a User Program). this would be an instant purchase for me. okay I'll stop dreaming now. thanks again.