Using SW2015 SP4. I have PhotoView360 Add-in active and can make photo renders. I choose "Save As" and select "LXO". Narration says "Preparing files for PhotoView" and Rendering PhotoView" and when it finishes, there is no file export. I can export to other file formats like STEP. I can "Save As" to a new SW assembly. I have tried using different assembly file to start from. I have reinstalled SW15 SP4. I have talked to support, who said to try SP5 (but I can't until my IT group finishes vetting it).
Export to LXO was working a few weeks ago. I know because I'm teaching myself Modo 901 and I've got a few renders from SW-created LXO files.
The other possibility is that some kind of Microsoft security update in the past month or so caused a conflict. I'm in Windows 7 Enterprise 64bit.