Hi there !
Im doing a project with some photos from 2015 and earlier, which are stored on an external hard drive. All was working fine 48 hours ago, when I was happily editing images in LR on my iMac.
Today, I have gone back into LR to do some more work - and although the external drive appears in the left hand menu, all the content folders have question marks over them. When I try to access the photos contained, they come up with the "this file is either offline or missing" message. So the same photos that were there a couple of days ago are now not being linked in for some reason ?!
Can somebody help me with this please, I do not wish to try anything myself in case I make things worse ...
This means the photos are not in the location where Lightroom expects them to be. It could be because you moved the photos or renamed them or deleted them outside of Lightroom. To fix the problem you first have to find the photos using your operating system, then you know where they are, and you can apply these instructions to fix the problem: Adobe Lightroom - Find moved or missing files and folders
The problem could also be the external disk is not plugged in, or plugged in but asleep, or otherwise not recognized by the operating system.