Symptoms
- Drive spins up briefly then stops, or doesn't spin at all
- Drive is detected but disconnects during heavy use
- Problem is worse on laptops, especially older ones or when on battery
- Drive works fine when connected through a powered USB hub
Likely causes
- CommonSingle USB port can't supply enough current for the drive's spin-up demandPortable hard drives can briefly need more power at spin-up than some ports provide.
- CommonLaptop limits USB power output while running on batteryMany laptops reduce USB power delivery to save battery life.
- PossibleUsing a passive, unpowered USB hubThese hubs split power among ports rather than adding capacity.
- PossibleWorn or low-quality cable causing voltage dropCheap cables can lose enough power over their length to matter.
What to do
- Plug the laptop into its charger, since some laptops restrict USB power on battery.
- Use a 'Y' or dual-USB cable if the drive came with one, plugging both ends into the computer for combined power.
- Avoid unpowered USB hubs; use a powered hub or plug directly into the computer instead.
- Try a different, shorter, higher-quality USB cable.
- Try a different USB port, ideally a rear port on a desktop rather than a front panel or hub.
- If the drive still won't get enough power anywhere, consider a drive with its own external power adapter instead.
Tools and parts
- Powered USB hub or dual-connector cable
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.