This document pertains to HP Notebook PCs with Windows Vista.
HP Notebook PCs have been encountered where USB devices stop responding or USBEHCI.SYS errors may display intermittently. If the bandwidth usage of these devices is heavy, the devices may behave incorrectly.
For example, you plug a USB headset with a microphone and earphones into a USB 2.0 hub. While you listen to music from the earphones, you use the microphone to record your voice. If the music is playing at a high bit rate, and you are recording at a high sample rate, you may hear some noise from the earphones.
This problem occurs only when you plug a USB 1.1 device into an external USB 2.0 hub. It does not occur when you plug the USB device directly into the USB host controller.
To avoid or fix this problem
To avoid this problem, connect the USB device directly into the host controller instead of into an external USB 2.0 hub. Or, reduce the bandwidth usage of the USB connection to reduce the possibility of experiencing this problem.
A supported hotfix is available from Microsoft. To resolve this issue using the available hotfix, download the hotfix by clicking http://support.microsoft.com/kb/968764 .
Contact HP service and support if you are experiencing this issue and feel that you need additional help.