Copying greyed out files between drives I am trying to copy data from an external NTFS drive to an exFAT drive.
However, some files are greyed out and give me this error when I try to copy them:
One or more items in “IMGP0029.AVI” can’t be changed because they are in use.

Even after clicking Continue and typing my password, it doesn't copy.
Following this answer I tried to run SetFile -c &quot;&quot; -t &quot;&quot; path/to/file.mov but I get:
ERROR: Write Permissions Error. (-61)  on file: /Volumes/Seagate Backup Plus Drive/IMGP0029.AVI 

Running sudo chmod 777 gives me:
chmod: Unable to change file mode on /Volumes/Seagate Backup Plus Drive/IMGP0029.AVI: Read-only file system

Where do I go from here?
My workaround (which might not be suitable for everyone) was to copy the data onto a Windows PC, and then onto the destination drive.