Hi @Ben_Thompson and @DaveN,
Dave, thank you so much for sharing a fix for Ben! I did feel it necessary to mention (for any future cases around this that may pop up) - after reviewing the details of this case, and because both current setups include custom theme modifications and manually edited files, it falls outside our scope of technical support.
Roon officially supports only the two built-in themes (Light and Dark). If the crash reproduces when using the supported themes, we can absolutely continue to look into this. If either of you would like to receive further assistance, please revert to a clean, unmodified installation using one of the default themes.
Thank you for the understanding here 