Today’s Question: After turning on the option to automatically write metadata to XMP [in Adobe Lightroom Classic], what happens if I exit Lightroom or it crashes while the process is working?
Tim’s Quick Answer: If you interrupt the process of saving metadata out to your actual image files in Lightroom Classic, the process will resume the next time you launch Lightroom.
More Detail: You can have Lightroom automatically save standard metadata values to the source image files on your hard drive (or XMP “sidecar” files for proprietary raw captures. This can be done by turning on the “Automatically write changes into XMP” checkbox on the Metadata tab of the Catalog Settings dialog.
If you have a large number of photos in your Lightroom catalog and had this option turned off, after turning the option on it may take some time for all of the updates to be written to the files on your hard drive. If that process is interrupted, such as by quitting Lightroom, the process will simply resume the next time you launch Lightroom.
In other words, you don’t need to worry about having had this option turned off previously, or about it being necessary to keep Lightroom running until the process is complete. That’s especially helpful since Lightroom won’t actually tell you when the process is completed after you turn on the setting in the Catalog Settings dialog.
So, you can rest assured that Lightroom will continue updating the metadata for files on your hard drive for all photos in your catalog, even if that process is interrupted along the way.