Update: I and others have found hfsplus support has been unreliable on Linux so I have converted the drive to EXT4. Read this post’s comments for more.
I recently purchased a 2TB external drive for my Linux media centre but could not work out why I couldn’t write to the drive regardless of the permissions I had set.
When mounting the drive I would get the following error:
mount: warning: /media/drive seems to be mounted read-only.
This is the solution I found thanks to a collection of findings on the web by firstly installing hfsprogs:
sudo apt-get install hfsprogs // For Debian based distro sudo fsck.hfsplus /dev/sdb2 // depending on your device and partition
Then try mounting the drive again as a normal user and hopefully it will work.