eSATA external HDD works with Windows 7, not Windows 8?

I have a LaCie 2big Quadra 4TB external hard drive, the older model that does not have USB3. Anyway, it has an eSATA port, as does my laptop. The eSATA port on my laptop is actually part of the Intel HM76 chipset, not some half-arsed jmicron add on.

On Windows 7 x64, the hard drive worked perfectly when using the eSATA port. It did not require any third party drivers either. Now that I'm running Windows 8 Pro x64, the hard drive does not work using the eSATA port, only the USB2 connection. When I plug it into the eSATA port, it shows up in Device Manager listed under Other Devices, with a gray (not yellow) question mark over it. It is not accessible from My Computer, nor does it show up in Disk Management.

If I plug in using USB2, it works just fine, but much slower of course. I've tried with and without the latest Intel RST drivers installed -- it makes no difference. Anybody have any ideas as to why it won't work in eSATA mode using Windows 8?

Have you looked in the bios setup to see if its showing there? Have you done a rescan for drives in disk management - under "Action" at the top? Are there any bios updates for your laptop?

It does show up correctly in the BIOS. Doing a rescan in Disk Management still does not result in anything. My BIOS is current. What on earth could be causing this? It works perfectly on Windows 7.

Can you find the error code in device manager - these 2 links below may help:

Troubleshooting Device Conflicts with Device Manager

Explanation of error codes generated by Device Manager in Windows XP Professional

Nope -- there is no Resources tab in the properties sheet for the drive, so no way to see any potential error codes. What is strange is that the drive does not have a yellow exclamation mark or question mark, as many problematic devices I've seen in the past. Instead, it has a less serious looking gray question mark. Nor is it listed in unknown devices -- it is listed in Other Devices, and the name of the device correctly identifies it as the LaCie external hard drive...

Are you dual booting with W7 & W8 on the laptop? How did you hook it up to the laptop - did you shut down the laptop - connect the drive - turn it on, then start the laptop - could be worth a try if you didn't unless it came with specific instructions.

No dual booting. I just plug it into the eSATA port, as I did in W7. It won't work if I plug it in while the computer is on, or if I plug it in before the computer is turned on. On W7 it showed up as a plug and play device in the system tray with the ability to safely remove.

Try support, and the forums at the LaCie site, and or contact them. If that doesnt bring anything to light - depending whether you deleted the w7 partition during install -if you didnt do a custom install, and select drive options or words to that effect - delete the windows 7 partition and then select create leave size as default and then select install. Maybe that will remove w7 corruption to the MBR on the disc.