What number version of Lightroom?
What operating system? Windows? Mac?
How is the external drive formatted? (ntfs, fat,?)
How did you add new photos to the folders on the external drive?
What do you see in the Import dialog of Lightroom?
Have you selected the drive in the "Source" location of the Import dialog?
CC 2015 is version of LR
no idea ntfs or fat
copied from camera
not sure what you mean "what do i see" but in "Import" i see the full list of what i am trying to update. When i select one of the new folders, for one second the five new pictures within flash on the screen then disappear and it's blank, meaning "there are no new photos"
Yes, the sources are all listed.
Do those images have the same name as any other images currently in the catalog.
Try searching in the catalog with All Images active. (Upper left of screen in the Catalog Panel) for one of the filenames.
Are the new images perhaps in subfolders.?