Why does my external drive keep disconnecting?
Short answer
A drive that drops out now and then usually has an ordinary cause. Western Digital lists loose or faulty cables, sleep and standby modes and file system issues among the common reasons a drive randomly disconnects. Hubs matter too: Apple tells Mac owners to connect a drive directly to the Mac. While it still connects, copy anything irreplaceable off, and note when the dropouts happen.
Intermittent is not the same as absent. A drive that vanishes and then reappears usually has an ordinary cause in how it is connected or how the computer manages it, not in the stored data itself: Western Digital lists loose or faulty cables, sleep and standby modes, file system issues and the computer system or BIOS among the common causes. The checks below move from the cable outward, each testing one part of that chain.[1]
Start with the cable and the port
Swap the parts that cost nothing first. Seagate's troubleshooter advises trying a different port on the computer, using a different cable if you have one, trying a different computer altogether, and connecting without a USB adapter if you are using one. A swap that settles the drive is the answer.[2]
Check the power, not just the plug
Desktop drives with their own adapter need it working properly: Seagate says to check the drive's light is on, try a different wall outlet, and plug the adapter straight into the wall rather than a surge protector or power strip. Hubs are the portable equivalent. Apple explains that anything plugged into a Mac's ports can request only a limited amount of power, and recommends connecting the drive directly to the Mac rather than through a hub, giving a self-powered hub its AC adapter.[2][3]
When your computer puts the drive to sleep
Computers can switch idle ports into low power states, which can look like a dropout. Western Digital tells owners to make sure the drive and computer do not go into sleep or standby mode, and notes that a drive locked with WD Security will lock itself again when the computer sleeps. Windows is deliberate here: Microsoft documents selective suspend as a feature that suspends an individual port to conserve battery power, one that is enabled by default and that Microsoft strongly recommends not disabling. Checking your sleep settings is reasonable; switching power management off everywhere works against the design.[4][1]
Copy what matters off the drive while it still connects. Intermittent is not the same as gone: nothing in these symptoms by itself means data has been lost, and the drive is readable each time it reappears. Seagate's repair advice draws the same line: only repair a drive that is not the only copy of your important data. Copy in small batches, most important files first, so a dropout interrupts a few minutes of work, not an evening.[2][1]
When the signs point at the drive itself
If a different cable, a different port and a different computer have all made no difference, the drive's own electronics move up the list. Seagate is blunt about the end of its checklist: if you see Code 10 and have already tried another cable and computer, the drive has probably failed, and it points owners who still need the data towards a recovery service. Dropouts that continue on every cable and port fit that picture.[2]
While you work through this, keep a note of what happens: when it dropped out, what the drive was doing, and which cable, port and computer it has happened on. Each check is a comparison, and the note records which you have already run.[2]
Two neighbouring situations have their own guides: a drive that stops appearing at all has moved from intermittent to absent, and one that appears but will not open was never a connection problem. And whenever you unplug on purpose, eject properly first.
External drive not detected at all
External drive detected but inaccessible
How to safely remove a USB drive
Sources
Facts on this page are cited to the publishers’ own documentation.
- [1] Western Digital — Learn How to Resolve External Drive Disconnecting on Windows and macOS. captured 2026-09-13.
- [2] Seagate — USB external troubleshooter. captured 2026-09-12.
- [3] Apple — USB devices disabled on Mac (Apple Support). captured 2026-09-12.
- [4] Microsoft — USB selective suspend. captured 2026-09-12.