Swap another identical cable, as it’s the cheapest way to isolate the problem.Ī faulty power connection. Cable failure is more likely for drives that are routinely connected and disconnected to a computer. This is true even if it’s the one included with the drive or you purchased one from a company with strong positive product reviews. Even if you haven’t touched the cable since you attached an external drive years ago to a desktop computer, cables can fail. Here are five other possibilities and some accompanying ideas for troubleshooting:Ī bad cable. This may reveal other problems, but it’s important you have as current a copy of what’s on that drive as possible, as the hardware may be about to die-or the drive may at least be hard to access while you work through solutions. If unexpected unmountings continue, try to make a backup immediately. It’s worth trying, because it’s non-destructive. Some readers have found this problem is related to system software, and they go through the standard set of hardware parameter troubleshooting, such as resetting NVRAM and resetting SMC. The message “Disk Not Ejected Properly” usually appears when you unplug a cable or disconnect power to a drive without making sure the disk has unmounted from the Finder after selecting it and choosing File > Eject or clicking the Eject icon next to its name in the sidebar. If you’ve found that your previously reliable external hard disk drive or SSD starts ejecting itself, trouble is obviously afoot. When you mount a drive in the Finder, you expect it to stay there.