Large external HDDs not always recognized; time-out issue?

I apologize in advance for the length of this post, but I want to be thorough.

I have an intermittent problem with external (hot swap) hard drive recognition.

I have the following docks:
> Icy Dock MB171SP-B, internal SATA, powered like an internal drive
> Rosewill RX-358 V2 SLV, using eSATA (also has USB 2.0), external power supply
> StarTech SATADOCKU2E, using eSATA (also has USB 2.0), external power supply

These devices are all connected to the following PCIe card, for which the driver is up to date:
> SIIG SC-SA0R11-S1, DP SATA 6Gb/s 4-Port Hybrid PCIe

I have three external hard drives, all GPT:
> Seagate Barracuda ST3000DM001, 3tb, 7200 rpm (data backup #1)
> Toshiba DT01AC300, 3tb, 7200 rpm (data backup #2)
> Seagate ST3320620AS, 320gb, 7200 RPM (older drive, miscellaneous files)

My PC has the following:
> Gigabyte GA-Z77-DS3H motherboard, set to AHCI
> Windows 7 Pro, 64-bit
> C: is a Crucial MX200 250gb SSD (GPT)
> D: (data) is the same model as the backup Toshiba 3tb (GPT)

The Seagate 320gb drive is always recognized quickly in all three docks. When recognized, the 3tb drives will take longer.

But sometimes one of the 3tb drives won't be recognized, and it's happened with both of them. I'll get the Notification Tray balloon telling me the disk's driver has been loaded, but that's all. There's no other message, the drive won't show up in Disk Management or Device Manager, and scanning for hardware changes in Device Manager won't find it. If I shut off the dock's power switch, Windows returns a message telling me that the drive must be formatted, even though (a) the drive is formatted and has data, and (b) it is effectively disconnected.

I can't seem to repeat the problem right now (of course!) but I ran a test with the two external docks using USB 2.0, and Windows took about the same longer time for drive recognition as with eSATA.

> I read somewhere that Windows has a time-out setting for detecting drives, and my experience would seem to support that. Is this a known issue? If so, can the time-out be changed?
> I use HotSwap! for HDD removal. Could this be the problem?
> Or is there something else I'm missing?

As noted, the problem is intermittent, so it's difficult to test.

Thanks in advance. I appreciate any help that can be offered.

Some more testing....

This afternoon I found that the problem was occurring again, so I shut down and connected the Icy Dock and the Star Tech's eSATA port to open SATA ports on the motherboard. I set the ports to hot swap in the BIOS and restarted, this time with the Toshiba 3tb drive running in the Icy Dock. Windows gave a message about loading the device driver and then prompted to reboot. I let it do that, and when I tried after reboot to remove the drive with HotSwap!, it wouldn't let go. It said that the drive "cannot be uninstalled right now because the device requested a system restart." The only safe way I could stop the drive was to shut down.

I reconnected the Icy Dock to the PCIe controller and tried again with all three of the eSATA docks. It was not recognized with the Icy Dock or the Star Tech, but it worked with the Rosewill. These tests were all with the Toshiba 3tb drive.

Just to cover the bases, I switched the Star Tech to USB, and it worked, both connecting and disconnecting. I can use that, of course, but it's slow, especially for backups.

This is driving me nuts. There are too many variables to focus just one dock, a bad cable, etc., so I figure the problem must be somewhere in Windows.

BTW, I didn't mention this before, but the PC is running Intel RST. I updated it via Gigabyte's Download Center, but it didn't make any difference.

I've been digging around the web, and it appears as though Intel RST has been the source of my trouble. Although it seemed as if my problem just started recently, I figured what the heck. I uninstalled RST and replaced its driver with the generic SATA driver in Device Manager, and external disks seem to be working properly now, even in the 3tb size.

I don't want to mark this solved just yet, though. I want to put the system through these paces for several days before I feel confident about that.

I think the problem is solved, for the most part. Drives running via eSATA to a separate controller card are recognized and disconnected properly.

The exception is a 4tb Hitachi drive. It will only be recognized properly when connected to one of the motherboard's SATA ports and it won't disconnect properly without a reboot or shut down. The Windows "safely remove" routine reports that the drive is in use -- although for what, I can't determine. HotSwap! advises that the device has requested a restart, and when I close that popup, AutoPlay starts as if I had just connected the drive. However, I think I know the reason, which is unrelated to my overall problem, and right now it seems to be more trouble than it's worth to deal with it.

The bottom line is that my hard drive recognition problem seems to have been solved by uninstalling Intel RST and its driver.

Oh, how I hate to write this, but this problem is Not Solved after all. I'll be darned if I know what's happening, but while both of my data backup drives (3tb each) are recognized to the point of the driver being installed, only one of them shows up in Windows Explorer. They both show up in Disk Management and Partition Wizard, the latter of which tells me that there is data on the drive (as it should), but one does not show up in Windows Explorer, and when I click on HotSwap! the one that isn't recognized is there, but without the disk label.

This happens with an external dock using eSATA, an external dock using USB 2.0, and an internal dock that is connected to a motherboard's SATA port. All three docks work with the other backup drive, so it can't be a dock problem.

I suppose the unrecognized drive could be corrupted somehow, but I can't imagine how that would happen over the course of a day or two when the drive is out of use and stored securely.

I'm sorry to be a bother, but if anyone has any suggestions, I'm all ears.

I did some more digging, and a page at Microsoft's website gave me a clue that had never occurred to me. Among other things, it said to make sure the drive has a letter assigned in Disk Management.

It did not.

I don't know why that would happen, but I assigned it the letter F (the usual default for a second hard drive unless I specify otherwise) and fast as I could say abracadabra, the drive showed up in Windows Explorer.

It would seem that this has been at least part of my problem. Again, I don't know why a letter would not be assigned automatically, but there it is. I'll mark this Solved once again.