He clicked a magnet link on a thread that had been dead since 2019. The peer-to-peer client stalled.
This is the #1 mistake new users make.
When MAME updates to version 0.79, the file requirements change. mame 078 plus romset
The (often referred to as the MAME 2003-Plus reference set ) is a specialized collection designed for high-performance arcade emulation on low-power devices like the Raspberry Pi, mobile devices, and older PCs. It is an evolving expansion of the classic MAME 0.78 set used by the mame2003 core. Core Concepts He clicked a magnet link on a thread