The (free) special promotional Libraries were released at specific times for specific products, not all of the Waveform data is readable by the current products. The XF promotional material will not completely load to the MONTAGE/MODX. Some of the Waveform data in those promotional libraries was quite old at the time it was released - dating back to the end of the last century.

Since the S90 ES never loaded Waveform data, therefore, you must be referring to the S90 ES acoustic piano (a favorite) that was included in the Ultimate Piano Collection.. The MONTAGE/MODX has that legendary data resident in the Factory Wave ROM. Please recall “S700 for Montage” — this is the S90 ES Piano updated for use in the MONTAGE/MODX.

The S80, S90, S90 ES introduced a specially sampled $250,000 handcrafted Yamaha S700 acoustic piano Waveform Set. In the S80, some 20+ years ago, it appeared as a medium strike, (non-chaotic) Waveform Set. It was met with great acclaim. A more detailed version was included in the S90 (2002)... And by the time it evolved in the S90 ES (2005), it was a three Waveform Set, with its silky smooth tone.

The S-Series was the non-Workstation versions of the Motif-Series (they were Motifs without the Integrated Sampling Sequencer), and thus the great demand for this special S-Series acoustic piano by Motif owners... which is why it was included in several of the Motif and MO-series promotional giveaways.

What you can do
This is also why a version was burned into the MONTAGE/MODX Factory Wave Set.... looking for the S700 acoustic piano for Montage... find it “S700 for Montage”, it’s in there.
Updated to take advantage of the many improvements to the AWM2 synth architecture in the past 20 years. In the MONTAGE/MODX it is now a four-way velocity switching sound with Key Off Sound... (you can remove if you want to sound like it did 14 years ago when that feature was not yet included in the sample engine). You’ll have to suffer with its improved audio path and effects, but if you and your friend are true fans of the S90 ES acoustic piano sound, as I have been since day 1, ... you’ll love the S700 for Montage (same programmer) updated with loving care. If you, or your friend, still have an old S90 ES we invite you play them side-by-side. As you might imagine, at the company there are tons of great stories and history behind that particular S700 sound... the S-Series, the Motif... trust me, there was no way it was not going to be in the MONTAGE! haha! Enjoy!

Hope that helps.