Please check if you have Full read/write permissions of your External drive.
yes i do
actually, i used it since 2014.
What happens when you try to import?
i am shooting on a cannon 5d, m4...raw and jpeg, and Lightroom will not allow for imports since I added raw to the camera setting...Help???/
Preview unavailable for this file shows up
That sounds like your camera is newer than your version of LR, thus LR cannot read the raw files.
If that is the case, a simple update of LR should solve the problem.
See this link for details: