For most USB storage devices and USB host controllers, the power-saving mechanism works without issues. However, a pre-existing problem in the USB drive or USB host controller might cause these problems after the specified idle period expires:
•The device periodically disconnects and might reconnect leading to poor user experience.
•If you try to access files stored on the drive, Windows Explorer becomes unresponsive for 1-2 minutes.
If you notice any of those problems, first check whether the firmware on the USB host controller or the USB storage device is out of date. If so, get the latest firmware from the system or device manufacturer. A firmware update might resolve the issue.
Otherwise, determine whether the problem occurs during the system disk idle time period (shown in Power Options). If it does, disable suspend on idle for this device as per the instructions given in the next section. Note, you can set the value to “Never” in the Power Options just an experiment to see if that fixes the issue, but the right long term solution is to set the registry setting as described below. This registry setting does not affect the other USB storage devices and results in conserving power.