IDT High Definition Audio CODEC 6.10.6491.0 installed in our HP Envy Notebook - C8U19AV with Windows Pro 8.1 64 bit OS, the system will lose the driver. When I go into device manager it appears that the codecs are there but the driver for the audio just gets lost. We have to repeatedly uninstall all the audio components and then reinstall again. This has been the situation for some time. I cannot say for sure but I have reinstalled the driver twice now for my wife and she has done it a few times. We commonly use the laptop connected to an HP2710m display monitor with an HDMI cable. From time to time we plug in Bose headphones as well. The diver revision 6.10.6491.0 was again installed today after fully uninstalling the prior driver. The common signature is the sound does not work at some point and when I go in and check on the audio codec it will report no driver loaded. Any attempt to run the sp63407 install package without ripping out everything will result in the driver install failing as some of the prior files will has security that prevents the over write of the old files with the new ones.
I can seen no obvious reason for this laptop to repeatedly lose the driver. Once the reinstall is done the sound works again but it is a real bother to have to repeatedly reinstall the audio driver.