Check whether the file is uploaded
Find the file in its destination. If it is missing or the upload panel shows an error, troubleshoot the upload first. If the file is present, its preview may still be processing. Avoid uploading repeated copies to fix a preview.
Image, video or PDF thumbnail
- Open the file’s action menu and choose Settings → Thumbnail.
- Choose Reprocess thumbnail if it is offered. Wait while the thumbnail is queued or processing.
PowerPoint slide previews
For a .pptx file, open Settings → Slides. If Generating slides is shown, preparation is not complete. Otherwise, choose Analyze slides, or Reanalyze slides when slides already exist. Thumbnail reprocessing does not generate individual slides.
Video playback preview
For a stored video, open Settings → Video → Preview. Choose Generate browser preview, or Regenerate browser preview if one already exists. This creates the playback preview; it is separate from the thumbnail. Video tools are disabled for external files.
Still missing?
Check that the original opens normally on your device. Send support the file’s location, the action you tried and any error message or processing status.