I have a Western Digital MyBook external hard drive. It generally works fine, but often when I try to copy a file to the drive, I get "The operation can't be completed because an unexpected error occurred (error code -50). If I try using the
cp command in the terminal instead, I get "Invalid argument". If I then try to eject the drive and remount, everything works fine.
It seems that these hard drives spin down after about 10 minutes of inactivity. That doesn't really bother me, and I'm not positive this is the issue, as I can browse around the drive fine once it spins up again, but I still get the copy error.
Disk format is Mac OS Extended (Journaled)
cp command I used:
cp /Users/Ben/Desktop/test.txt /Volumes/Media