Today’s Question: When I assign a star rating to a photo in Lightroom Classic, why doesn’t that star rating show up in Bridge?
Tim’s Quick Answer: By default, metadata updates applied in Lightroom Classic won’t be visible in other applications, though you can change this behavior. However, it is also important to remember not to update metadata in other software if you’re using Lightroom Classic.
More Detail: Lightroom Classic saves metadata first and foremost in the catalog, without updating the source image files. By default, any metadata updates you apply in Lightroom Classic won’t be visible in other applications.
If you want updates to standard metadata fields to be visible in applications outside of Lightroom Classic, you’ll need to change a setting in the Catalog Settings dialog. To get started, go to the Edit menu on Windows or the Lightroom Classic menu on Macintosh and choose Catalog Settings. Go to the Metadata tab in the Catalog Settings dialog and turn on the “Automatically write changes into XMP” checkbox.
With this checkbox turned on, standard metadata updates will be saved both in the Lightroom Classic catalog and in the source image file. For proprietary raw captures those updates will be saved in a sidecar XMP file rather than the original raw file. This allows those updates to be visible in other applications, including Adobe Bridge.
Keep in mind, however, that this option only relates to standard metadata fields, such as star ratings, color labels, keywords, and more. It won’t preserve features that are specific to Lightroom Classic and therefore can only be saved to the catalog, such as collections, virtual copies, or image stacks.
While saving the metadata to the source image files will enable other applications to display the updated metadata, making changes to metadata outside Lightroom Classic will cause a metadata mismatch, and therefore you should only make updates within Lightroom Classic.

