Let me know if I understand correctly: both at Guitar Center and at your own keyboard - you see the same results. At Guitar Center, the keyboard can load one of the two 3rd-party XF sample sets and appears to work correctly (making sound). On the other hand, the second XF sample set does not make a sound both on your own keyboard and the one at Guitar Center.

I just want to make sure you haven't seen a difference between the two keyboards tested.

The no sound issue is most likely due to a compatibility issue with some waveforms that, for lack of a better way to describe them, have some form of "copy protection" in them. You may get other ways to describe these - but it is true that certain files that are encoded a certain way have known issues. Despite being known, I am not aware of any fixes that have addressed this.

If you can add details on what the sample sets are exactly - we have seen previously that, at least in the case of "EasySounds" material - that the company has made available new/corrected files that work with Montage.

Also, if this is the real issue - then you could try contacting the company/entity that released the sample set to begin with and state some problem with compatibility on the Montage. Like EasySounds, they can "redo" the release to be sure Montage is happy.

Another limitation of the converter (inside Montage) is that it does not provide support to convert Performances.

Some previous posts:

https://yamahasynth.com/forum/inspiration-in-a-flash
https://www.yamahasynth.com/forum/inspiration-in-a-flash-1

This is the "latest official" word from Yamaha pulled from the first link:

As to the data in the "Inspiration in a Flash" Motif XF file, it has been determined that many of the sounds in that compilation (including the S700 data) do not translate from that to Montage, directly. There is a definite incompatibility with certain Waveform data in that file.