Picture Taker Loc: Michigan Thumb

I kept my Mac to the old system also. What I have always done is put a folder ( I name it by date 080420) on my Desktop and dump it in to that. Now I have it on my computer and can do what I want to. I will HDR them or put them in my Aperture or what ever.
The option iOS to use a external drive and store all the pictures as taken by date (to keep) and the take them to do as you like.

a6k Loc: Detroit & Sanibel

iOS is only on the iPhone and older iPads. MacOS X is what a Mac computer uses. A detail perhaps but it can be important when trying to look something up on the 'net.

Sinewsworn Loc: Port Orchard, WA

JD750 Loc: SoCal

Just close Lightroom and open Image Capture.

kotography4u

Easiest way I know of is to remove your card from your camera, insert card into the card slot on the side of your iMac, wait for it to appear in Finder as Nikon SD card or whatever your computer chooses to call it, open in Finder the folder containing the pics you want to copy, click the first pic in the column, then scroll down and Shift-Click the last one you want to copy. This will highlight first pic, last pic and everything in-between. Then Command-C to copy them. Then go to (or create) folder on your hard drive in Finder where you want to deposit them, open that folder and click in the blank space in the folder to tell the iMac where you want them to land, and hit Command-V, and the computer will copy the files there. LR not involved. BTW - decline your computer's constant suggestion to "upgrade" or "update" your OS from High Sierra. My understanding is that LR6 won't run in Mojave. Someone may correct me on that, but I think that's correct.