I just noticed that the link for this is not live on Yamaha's download site. Is there some problem with it?
Can someone let us know when it would be a good idea to download and install it?
I also notice that there is no link for the 1.9.10-2 Windows latest driver download on the Montage page or the download.yamaha.com page for the drivers. ( https://usa.yamaha.com/support/updates/index.html?c=music_production&k=montage )
Steinberg does provide a link for the driver:
https://www.steinberg.net/en/support/downloads_hardware/yamaha_steinberg_usb_driver.html
However - the lack of a link from Yamaha (Montage pages) does beg for the OP's question if there was a reason beyond a website error ("oopsie") why the driver is not available from Yamaha's Montage pages.
Note that you can find the 1.9.10-2 driver on Yamaha pages other than Montage (pro audio pages):
http://www.yamahaproaudio.com/global/en/downloads/firmware_software/yamaha_steinberg_usb_driver/
Both the Steinberg page and Yamaha Pro-Audio pages provide the same file:
Filesize: 6,016,708 Filename: YSUSB_V1910-2_Win.zip
Current Yamaha Synthesizers: Montage Classic 7, Motif XF6, S90XS, MO6, EX5R