How to scan for keywords

Occationally my keywords seem to just disappear.

I'm sure it's a cache issue. So I created a new folder on a larger drive, but I need to tell Bridge to scan all the videos there for the metadata that holds the keywords.

If I type in "car" in the search panel (looking for everything with "car" keyword) it says "no item in folder", even though I have a thousand images with "car" keyword that were searchable yesterday.

Alternatively, I can go into a folder, highlight the videos, and then the keywords register, and if I type "car" again, it will recognize where it is and show me.

However, I have like 20k videos. Is there a button that I can click that scans a folder (and sub-folder) to recognize the keywords of all the videos/images? It will take forever to open each folder, highlight the contents, then move to the next folder.

Thanks in advance.

Van