None of the Windows PCs and Servers hereabouts shipped with “native” USB3 ports, so they are provided instead by an assortment of el-cheapo PCI cards I purchased years ago. All of those cards happen to use the Fresco Logic host controller chipset… and every single one of them has misbehaved of late when running Windows 8.1 or Windows 2012 R2.

The symptoms are that brand new USB3 hard drives are plugged into the Fresco Logic-supplied USB port, bulk file copying begins to the newly-available USB drive and then, sometimes swiftly or sometimes after considerable time, the copying option aborts with a 'destination drive no longer available' error message. You usually get the option to try again, and if you do, the bulk copy operation resumes (though the specific file that was being copied at the time the error arose is skipped in the process).

This happens repeatedly. It happens with (in my case) three different WD Elements USB 3.0 2TB drives using 6 different USB 3.0 cables (just in case!). It happens with Windows 8.1 and Windows 2012R2 equally. And it happens on 3 different PCs or Servers. In fact, the only commonality that can be traced is down to the use of Fresco Logic hardware as the USB controller.

It's all just a bit annoying …and if you Google the phrase Fresco Logic USB Windows disappear, you'll find that randomly-disconnecting USB drives courtesy of Fresco Logic hardware isn't exactly a rare phenomenon. The general theme running through all those other stories of woe is that the Fresco Logic power management capabilities are a bit aggressive (putting it mildly!) and thus the USB drive is constantly being turned off and on again by the controller in a misguided fit of power saving.

What resolved the matter for me was:

1. Go to Control Panel → System and Security → System → Device Manager, expand the Universal Serial Bus controllers item and right-click the Fresco Logic Root Hub item and select Properties. Select the Power Management tab and uncheck the option to allow the computer to turn off the device to save power. (Note that this option seems to re-check itself after a machine reboot -or, indeed, after a drive disconnect and re-connect, so although I did do this step, I don't think it actually made any difference in the long run).

2. Use regedit (usual warnings about editing your registry by hand apply) to navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\FLxHCIc\Parameters\. If there's a REG_DWORD value there called U1U2LowPower, then set it to 0. If it doesn't exist at all, then just right-click and create a new 32-bit DWORD of that name with a value of 0. Having changed the registry, a reboot would be in order -though I found that merely disconnecting and re-connecting the USB drive seemed to do the trick.

Step 2 was the one that seemed to make all the difference to two of my machines: I still got the very occasional disconnection, but a 1.3TB file copy worked perfectly immediately after implementing it, where it had been continually failing before.

Just in case, however, you might note that at the time of writing, Windows 8.1 and Windows 2012 were both declaring that Fresco Logic driver version 3.5.4.0 was in use (installed from some ancient installation package I had lying about, but declared fully up-to-date when the 'driver update' button was pressed in Windows' Device Manager utility). From the Fresco Logic support site, you can actually obtain version 3.5.107.0. I haven't installed that myself, though: the regedit did the trick for me. I am reluctant to add yet another 'degree of freedom' to a problem that seems now to be resolved but proved frustratingly awkward to get that way.

Anyway: long story short… if you're using Fresco Logic hardware, my commiserations. And disable its silly power management capabilities ASAP.

~~DISCUSSION:closed~~