I have two internally mounted 3.5-inch spinning SATA hard drives that occasionally vanish from File Explorer, roughly once a week. Restarting the computer brings them back every time. Since it has happened with different drives, I'm not sure whether the problem is the drives themselves, the power connections, Windows power management, or the controller. The PC uses a Corsair CV450 450W power supply. Is there an obvious cause, and is there a way to refresh or restore the drives without rebooting?
3 Answers
When it happens, check Device Manager under Disk drives and use “Scan for hardware changes.” Also check Disk Management with diskmgmt.msc; the drive may still appear there but be marked offline. If so, bringing it back online may restore access without a reboot. It’s also worth disabling the option that lets Windows turn off the drives to save power, since some SATA disks don’t wake correctly.
Check the drives’ SMART health data with a utility such as a disk-monitoring tool. If the disks look healthy, the issue could be power delivery, a loose connection, or a SATA controller problem rather than the drives themselves. The next time it occurs, Device Manager and Disk Management should help show whether Windows lost the hardware entirely or merely stopped mounting it.
Power is still worth investigating, even if different drives are affected. Two spinning 3.5-inch disks can briefly draw more power when starting or spinning up, and an intermittent SATA power connector or daisy-chained cable can make multiple drives disappear. Reseat the connectors and, if possible, try separate power connectors or cables. A 450W supply may be adequate for the whole system, but its condition and the quality of the drive power connections matter.

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