Photos on iMac M1 not importing Nikon NEF files with disk space error

NEF files are importing properly for me. You didn't say what OS you're using-- I'm still on macOS26.

There are several ways to import pictures into Photos. I just tried dragging them in, and that worked. How about using File>Import? That also works for me.

You didn't say:

• Do jpgs import OK?
• Do you have more than one Photos Library? 
• Where does your Mac's Photos Library reside-- in the Pictures folder of your internal drive, or on an external drive? or on a network? on iCloud drive?
• Are you using iCloud Photos to synchronize your devices? If so
• …Do you have “Optimize Storage” checked in Photos’ Settings
• …Do you see all your Mac’s Photos  pictures at iCloud.com?
• …Have you checked to see if the Apple Account is really really the same on the Mac and at iCloud.com?
• …What is your storage at iCloud.com? At System Settings>[name]>iCloud>Storage , my Mac says 176 GB of 200 GB used. What does yours say?
• What is your storage on this Mac? At System Settings>General> Storage, my Mac says 745 GB of 1TBB used. What does yours say?

Try these things:

• Restart the computer (of course)
• Re-start in Safe Mode. This bypasses certain potentially disruptive processes, and it often helps. Safe Mode is different for different computers, so see this: 

           Start up your Mac in safe mode - Apple Support 

• Rebuild your Photos Library--close Photos and re-launch by option-command-clicking the app icon. If you use iCloud Photos, it’s possible that this will cause a re-sync that lasts long enough to make you nervous. I usually turn off wifi when I do this.
• Use another library if you have one, or make a small test Library with a few pictures in it and see if the same thing happens. You can create a new Library by closing Photos and then option-clicking on the Photos icon.
• Make a new user and see if the same problem recurs with it. This is a bit harder, because a new user can't access a different user's stuff. You would need to temporarily move your Library out of your own user's Pictures folder up to the general "Users" folder.

The idea is to find out if the problem is with the Library, with your account, or with caches and login items, and stuff like that. One of these steps may fix the problem, but their failure to work also helps figure out what's happening.

Let us know about our questions and what happens when you try things…

How is your external drive formatted? To avoid damaging the Photos Library, an external drive must be formatted in either APFS format or Mac OS Extended (Journaled) format. The drive must be connected directly to the Mac by cable, not networked, clouded, NASed, etc. Additionally, the drive can not have had Time Machine on it since it was formatted. There have been so many problems with using incompatible drives that the newest macOSs won't even allow a Library on a non-Mac formatted drive to open, since there is a chance of damaging the Photos database. See this:

Move your Photos library to save space on your Mac           

If this drive is in a an incompatible format, stop running Photos with it immediately!  A Photos Library can sit on an incompatible drive, but running it may corrupt the database.

You might also want to check the permissions for your new drive, if you're sure it's properly formatted.  This is not usually a problem, but it sometimes comes up. Click on the drive icon, and open the Info window with command-i. Go to the bottom:

If “Ignore Ownership” is there, then it should be checked.

You said "There is plenty of disk space where the Photos Library is located," but if the Photos library is on an external drive, you could still be running out of scratch space on the system drive.

jjk9 wrote: …Ok, I think I need to reformat the drive then. I will copy everything to another external drive and reformat this one. Thank you, this has been very helpful. I will report back after the reformatting and testing on the newly reformatted drive.

Great! ExFAT is an old format, readable and writeable by Macs and PCs, but it can't handle the sophisticated file handling and background processes in Photos. Be sure that your other hard drives are properly formatted, as well--ExFAT can cause damage to the database.

This was very helpful. I don't use iCloud so that isn't the issue.

I just made a new library on my System Hard Disk - my Photos Library is on an external hard disk. When I made the new library everything worked as usual, without a hitch. So, then I made a new library on ANOTHER external hard disk and also worked fine. So, clearly the problem is the external hard disk where I have my Photos Library. Even though I have been using the same disk for a while with no problems, but now, it just doesn't want to import new files. I am using OS 27 Golden Gate. Is there anything I can do to my external hard disk to eliminate the problem? without erasing it and starting anew? Maybe disk repair??

Ok, I think I need to reformat the drive then. I will copy everything to another external drive and reformat this one. Thank you, this has been very helpful. I will report back after the reformatting and testing on the newly reformatted drive.

[Edited by Moderator]

There is 318gb of free space on the system drive. Doesn't seem like that is the problem. I even tried to import just one photo with no success.