Today I encountered, after several trouble free years with Lightroom, the "unexpected end of file" error. I moved a batch of Nikon .NEF files, that were all shot on the same day, directly from the SD card to a folder on my Mac Desktop, and from there imported to Lightroom. When trying to Develop in Lightroom all the files from that day prompted the message "unexpected end of file" error. The same thing happened when I tried the same operation on another Mac running Lightroom. The corrupted images can be viewed and zoomed and look perfect in the camera's display screen, but cannot be processed using the camera's NEF (RAW) processing function or other editing functions. In Mac Finder the files show a range of sizes from 2MB to 12MB and show a thin or wider black edge to the image.
However, other files shot prior to the "problem" day using the same camera and SD card can be transferred without issue, and new .NEF shots I have taken today using the same camera and the same SD card have transferred and performed normally in Lightroom.
I've tried the "Fix" download but it doesn't work for me and, fair enough, that's not surprising as my camera is not among the models listed - Nikon D5100. I'm going to change SD card and do a periodic check via the in-camera RAW processing. I haven't provided any other "relevant details" as I don't know what details would be relevant in this case.
As far as I know, the "unexpected end of file" error can only be caused by corrupted files. Corrupted files are almost always caused by hardware malfunctions. Hardware errors can be intermittent, or affect portions of a camera card or hard disk, but not other portions of the same camera card or hard disk.
If you could post one NEF that isn't causing the problem and one that is on a sharing web site like DropBox and provide us the links, we can see if we can reproduce the problem.
What "fix" are you referring to? What is the exact version NUMBER of your LIghtroom Classic? What is the exact version NUMBER of your operating system? (We need the version NUMBER and not words like "current" or "up-to-date")
Are you using a Nikon tool to copy the files to the computer?
If yes, try to copy directly from the SD card using LrC's import.
Do you have already given acces to "all disc" to a PS and LR in preferences of MAC?
It's something new from BIG SUR, at least for me that I have a network at home. I have never done it in previous IOS.
I am Canon user with new MAC laptop and all programs updates to last versions and I was having corrupted photos (70%) after import in Lr (I used to import straight from Compact flash to a Lr and the photos are saved in a network disc). My problem has been almost solven by doing:
Preferences: Security/privacy go to "access to all disc" (left menu) then add PS and Lr.
Also in Finder go to "app", find PS icon app then right button to go to "obtein the information". At the bottom of that window, where "share & permissions" you need to add all (read & write) permissions to the "System" users.
Repeat this proccess with Lr.
I hope this can help you.