Sometimes is possible to mount partition in read only mode, if you have something important on that partition it is wise to make backup or safe copy.
This problem is usually in a dual-boot configuration or sometimes for removable disks.
sudo ntfsfix /dev/sdXY
riste@riste-K73E ~> sudo ntfsfix /dev/sda2 Mounting volume... The disk contains an unclean file system (0, 0). Metadata kept in Windows cache, refused to mount. FAILED Attempting to correct errors... Processing $MFT and $MFTMirr... Reading $MFT... OK Reading $MFTMirr... OK Comparing $MFTMirr to $MFT... OK Processing of $MFT and $MFTMirr completed successfully. Setting required flags on partition... OK Going to empty the journal ($LogFile)... OK Checking the alternate boot sector... OK NTFS volume version is 3.1. NTFS partition /dev/sda2 was processed successfully.
Replace XY according to your disk partition, you can see this in disks utility to see.
Microsoft introduced a new feature in Windows 8 and 10 to reduce the boot time in otherwise slow Windows OS. This feature is called Fast Startup. In normal shut down process, power is removed from all components such as CPU, RAM, CD-Rom and hard disks. But in fast
But in fast start up, Windows 8 saves some system information such as caching the registry etc to a file during shutdown. Part of the metadata about the state of all mounted partitions at the time of turn-off, is among these system information. This reduces the boot time of the Windows 8 but it creates the trouble for Ubuntu.
Since the information about the NTFS partition is stored in Windows 8, this prevents Ubuntu to mount them as mounting them in Linux will alter the metadata of the partitions. This is why it is in protected mode and you cannot mount it (without being root).
Temporary solution of this problem will be to boot in to Windows and restart it. Restarting is different from shutdown and it should release the partition metadata from the stored system information. But this will only be a temporary solution because when you use Windows 8 or 10 next time, you’ll face the same problem again.
Permanent solution would be to disable the fast startup in Windows 8/10. This will increase your Windows boot time so it is up to you if you prefer it. If you use Windows more frequently and you have probably set Window as default OS in dual boot with Ubuntu, then you should avoid this solution. But if you more of a Linux guy and use Windows occasionally then you can disable fast startup in Windows 10 without thinking twice.