Please look for
"Compatibility List for MOTIF XS 6/7/8、MOTIF XF 6/7/8 (As of August 2016)"
on
YAMAHA DOWNLOADS UNITED STATES

If it's there, you're good to go.

We use Lexar Echo Mx 2.0 8gb from way back 2013 when they appeared on the list.
If we hadn't over-bought then and had to do it again, SANDISK looks like our choice now....

Often more USB Flash devices will work than what is officially sanctioned by Yamaha.

Thanks Bubba and Monsignor. It's not on the list. This memory stick is USB 3.0 and theoretically it should work with USB 2.0 devices. I just don't know if this rule applies to MOTIF XF?! Does a USB 3.0 memory stick work with MOTIF XF USB 2.0 port?

This memory stick is USB 3.0 and theoretically it should work with USB 2.0 devices. I just don't know if this rule applies to MOTIF XF?! Does a USB 3.0 memory stick work with MOTIF XF USB 2.0 port?

"BACKWARD COMPATIBLE USB 3.0" is a good-read internet search.
Though, I've not used a 3.0 with our XF8's....as we over-bought 2.0's in the beginning!
If what I've read in the past, and to the point of not searching anymore for confirmation, when 3.0 technology was created, backward compatible was built in and is always available. (Anyone, please correct this if wrong)
However, the manufacturers in question should always be contacted ...

I'll say this with a caveat as we are most partial to Lexar Usb Drives, and even though the first thing that's needed is to remove their complimentary software that is included as it gets in the way of the Motif's, SANDISK wasn't on the list we first found.
We usually like security/password protection, storage in the cloud, etc.... but in this case, must be a clean drive and requires not only a format on the Macs but also on the XF. We then always run a test with one Allfile, and then see if the Mac will open it to view songs list while using MoTIF XF EDITOR app. I don't believe the Sandisk usb's offer these freebies.

If you want something now to get you started though, SANDISK(appears on current list) is an outstanding company of high quality audio and memory products (we use them in all our Nikons from very early on), and also, from a brief search of the Yamaha Compatible List (current), I found some by Sandisk that are 2.0 and 3.0. They are in a price range I like ie: under 10 bucks each. Maybe one of each and run a test, but 10 $$ is still $$! 🙂
By the way, I have bought all of our 2.0 Lexars from Amazon. As stated before if we had to do it again.... we'd try a Sandisk.

"Facts no Fiction"
"Safe not Sorry"
Our words to guide with... 🙂