Rhino no longer showing file preview thumbnails

Hello, a tired old subject, but my system has stopped showing file previews for newer files, seems to be related to latest service release (Version 8 SR25 (8.25.25328.11001, 2025-11-24))

  • running windows 11
  • older files show thumbnails
  • I have tried the various approaches elsewhere on the forum, best summarized by Dale Fugier under Saved files no longer have a thumbnail - #19 by milezee
  • did a) rhino repair installation, b) registering rhino thumbnail viewing c) clearing windows thumbnail cache, d) setting permissions in file explorer for thumbnails
  • I also tried saving a file to a new sub directory, in case I exceeded the number of files allowed, with no change

what else should I look for?

thank you