Just to close the loop - From another thread, Jack and I found that one of his themes had become corrupted at some point. He was able to find the offending theme and remove it, and the Update Out Of Date Themes process then started working. Here’s that thread. To try and find out which theme is corrupted, try exporting each theme, and seeing if 1) the export fails or 2) the exported theme causes trouble in another throwaway org’s “update themes” process.
