XnView Software

Using the full screen command brings up a full screen black screen.

From Browser, with selected JPG thumbnail:
using the toolbar View | Fulscreen
From Browser with selected JPG thumbnail:
using keyboard shortcut for Fullscreen

Both methods produce a black screen.

Using left/right arrow brings up the next image correctly. The black screen is disconcerting.

2022 MacBook Pro, Apple M2 Pro, Macos 15.2, XnView 1.9.0 64-bit (MACOS)

Preview panel is visible? Please send us your xnview.ini

Your comment of the .ini file pointed to the solution.

After researching my .ini file, I discovered a hidden .xnviewmp folder from 2022 on a connected external disk.

Removed the file, rebooted the computer. Problem solved.

Thanks again.