When plugging in my western digital to do a Time Machine backup the hard drive lights up. It has loaded and starts the backup but after a couple minutes an error message comes up. "The disk was not ejected properly. If possible, always eject a disk before unplugging it or turning it off." I left it plugged in and it has restarted twice and said the same error. But now it isn't showing up but the light is on. I do have it partitioned because at one time I was trying to help my sister backup her dell laptop, but her laptop has its own issues so I don't need the partition anymore. How do I fix the error or reset the hard drive to make sure I can make up my backups? I am also having issues with the computer running slow. I do have CClearner installed and ran a sweep last week. It helped but still had issues last week. I will include a screenshot of the error.