My system is having multiple internal hard disks and due to some memory concerns I have to work on the second drive(hdd2). Then on visiting "/mnt/hdd2", I found entire drive is protected by root. To change the privileges, I tried the normal way: sudo chmod 755 /mnt/hdd2 Result : NO CHANGE. Then tried sudo chmod a+x /mnt/hdd2 Result : NO CHANGE. No I googled I find: sudo chmod -R 755 /mnt/hdd2 Result : To my surprise NO CHANGE Here is the solution: sudo chown -R chaithanya:chaithanya /mnt/hdd2 Result : SUCCESS ('chaithanya' is the username).