When he plugged it back in and rebooted, SketchUp asked to recover an unsaved document. He clicked . He deleted the plugin folder, emptied the trash, and reinstalled the OS from a clean backup.
The silhouette turned.
v3.19 is widely considered the most stable version for modern SketchUp builds (v8 through 2018+), as it resolved permission issues and introduced the easier .rbz installation format. su2kt plugin download
The su2kt plugin is a [briefly mention the plugin's purpose, e.g., "popular browser extension"] designed to [mention the plugin's main functionality]. When he plugged it back in and rebooted,