Can't locate files using Finder or Spotlight (Catalina / New MacBook Air)

I suggest reading this Apple article and see if it improves your search results: Narrow your search results on Mac.

Using just the name of the file will search every filename and the text contents of documents, web pages, emails, ad nauseum. The following assumes that you have the Spotlight Search Results category Images selected.

Do a case-insensitive search for a partial filename string:

kind:image +.jpg name:advanced_

Compatible, external drives need to be mounted, and Spotlight must be permitted to index them before your search will be satisfactory. Depending upon the drive formatting, it may not be indexed by Spotlight.

Drag the mounted external drive icon onto the Spotlight Privacy window, wait about 10 seconds, and the select it, and click [-] to remove it from the Window. Do not eject that drive for at least an hour, though Spotlight no longer gives you a progress bar regarding indexing progress. I would do one at a time to not swamp your Mac with Spotlight indexing processes.

I have no experience with Spotlight indexing across thunderbolt adapters. If there is no inherent issue, the the first paragraph will index the external drive if it is not NTFS or one of the Linux formats.

Hi,

I have almost the same problem. Before I upgraded to Catalina on a Mac Book Air from 2015, Spotlight could find files on my two external hard drives. After changing for Catalina, it sometimes does and sometimes doesn't. It is as if it would erase the index.

The drives are formatted in ExFat, could this be the problem?