This can happen if the permissions on the destination folder has changed and or is not set to allow your username to write to that destination. With OS X that can happen at any time. So check the permissions on the destination drive/folder and or select a different destination in the import dialog window.
An update to my question...I tried importing to my hard drive, and that worked fine, so the problem is obviously my external hard drive. But why all of a sudden? What changed? And how do I fix it?? It is a Seagate Expansion Portable Drive, with lots of space still left on it. It's a 2GB drive with about 1.5GB left on it.
I did check this after reading another discussion on this forum and mine does just say Read only. But there is no lock on the bottom, and so it seems that I can't change the settings on it, unless there's another way to do that...Can you help me with that?
Did you recently upgrade your OS X version to El Capitan. How is the external drive formatted, Mac OS Extended or one of the Windows formats, NTFS or FAT32.
Does the external drive show up in a Finder window or an icon on your desktop?
99% of external drive are Pre-Formatted in the Windows NTFS format and unless you Re-Formatted it when you first got it to the Mac format it is still formatted in the Windows format. Maybe at one time you had a utility that could write to NTFS formatted drive and now that utility is no longer working. If you recently upgrade OS X to El Capitan it disable or removed that utility.
If you right click on that drive and select Get Info it will list the Format of the drive. Post what the format is.
Ah! Good questions! I DID recently upgrade to El Capitan, and the external drive is formatted Windows NTFS.
It shows up as an icon on my desktop and in Finder.
Then you have a couple of options.
At one time you DID have a utility that allowed Mac OS X to Write to NTFS formatted drives, OS X can't do that by itself.
You can get an update for that utility or find another that works with El Capitan, that's option one.
Or you can take this chance to Copy, that is COPY not move, all your images from that external drive to either another External or the Internal drive then Format that external to the Mac format using Disk Utility, that is option two and the one I suggest.
If you are sticking with Mac as a computer system then there is no reason to have any drives formatted in the Windows NTFS format.
If you still run a Windows PC and need to share files between Mac and Windows using an external drive then format that external to FAT32 which can be read and written to by both OS X and Windows
Okay, I'll take option two! That'll take some time to copy everything over, but at least then I'll be able to get things working again.
Thanks so much for your help. I'll get to work on this asap!
You're Welcome. Best of luck to you.
I ended up downloading a utility, as all my other external drives were Windows too, and that has solved the problem! In the future, I'll just reformat my drives to Mac format!
As I stated before if you plan on sticking with the Mac OS X platform it is best to start reformatting your drives in the Mac format. No better time to start doing that than on a Sunday.