Open an elevated Command Prompt (right click on the shortcut, click on “Run as Administrator”), and input: powercfg /h off If you still aren't able to mount without getting errors, you may need to turn off hibernation completely.
Now, shutdown Windows 8 and boot back into Ubuntu.
Hibernating saves the current state information to the hard disk and then powers down the computer.Turning it off the normal way (in newer versions of Windows, hibernate You are seeing this error because you hibernated Windows instead of Explanation: Why Linux can't open hibernated Windows partitions: Please do not run the command in this dialog unless you want to delete your saved Windows session and potentially lose unsaved work. A bug has been filed about the Nautilus dialog you are seeing as it recommends a potentially dangerous option that could result in data loss.