If you are getting “Read-only file system” on your Raspberry Pi when mounting drives there is a simple fix.
chewett@bunker-master2:/mnt/wd500$ touch test.txt
touch: cannot touch ‘test.txt’: Read-only file system
I noticed this happening when I tried to mount and work on my external hard drive. This is formatted with the NTFS filesystem.
I did some research and it turns out that by default Raspbian Jessie (as of 13/06/2017) does not include the ability to write to NTFS drives. To add this ability you can run the below command
sudo apt-get install ntfs-3g
This installs the NTFS driver which will allow you to also write to NTFS drives.
This issue will occur for anything using the underlying NTFS driver. I found this issue when I was mounting a veracrypt volume on the Raspberry Pi.
Veracrypt was installed by following my guide to install Veracrypt on the Rasperry Pi. Now I have resolved this problem I will be able to access my external drives on the Raspberry Pi.