I am running Lightroom Classic CC 7.3 with ACR 10.3. A friend with a new Fujifilm X-T100 sent me a couple of RAF files from his camera to play with. Lightroom won't import them. "The file cannon be opened by Lightroom." I can open the files in Photoshop (they open fine in ACR and then in Photoshop). They open in other programs as well.
Other RAF files that I've downloaded from the Web (that is not from his camera) open fine in the same instance of Lightroom.
The system is Windows 10 1809 (October 2018) with all updates.
Actually, the current version is LR Classic 8.0.
Many thanks to those who responded. I grabbed 7.5 and no more problem opening the RAF.