Does this message "no photos or videos were found to import" occur before or after you click on the Import button in the Import dialog box?
When the photos do appear, are they greyed out, or full color?
It appears after I click "import" - and it only gives me the option to click "import" if I'm fast enough before the photos are greyed out.
If I wait more than like 2 seconds - all the photos are greyed out and I can't check the boxes on any of them. So everything appears to be working normal initially, but then they all just go grey.
When photos are greyed out in the Import dialog box, taht means that you have previously imported the photos into Lightroom.
There is no reason and no benefit to import them a second time and so that is why you are seeing what you are seeing.
To make use of these previously imported photos, you go to your Library Module and you find the photos (by any one of a dozen or two means) and you do whatever you want to do with those photos, once you locate them.
I see now that I had imported them straight from the USB (not the folder on my desktop) and they had imported to that specific USB folder, not my Mac HD folder... (something I don't normally do!) So now your obvious answer has helped me discover my obvious mistake, haha.