The fast boot feature of Windows 8.1 allows a user to load Windows faster than ever before; but this can interfere with the mounting of the Windows partition from Linux. This forces the user to mount the partition read-only.
But if you use this command in a command prompt on Windows, this problem will go away. Run the CMD window with Administrator privileges and then execute this command to switch the fast boot feature off.
powercfg /h off
This is what solved my problem when dual booting with Windows 8.1 9600 and Linux Mint 16. Give this a try yourself and see how you go.