SATA drives keep disappearing after CMOS battery reset

I wasted days on this. Extremely difficult to pinpoint the problem. It started when my monitor went black. I removed the CMOS battery as a last resort to fix that. It didn't help. Then I realized I hadn't removed monitor power cable. That helped, picture was back.

Now I got a new problem. Very unstable SATA drives, they keep disappearing. I'm pretty sure the problem has nothing to do with BIOS or OS (Windows 7), because the problem is already seen on the boot sequence: gray text on black background, listing all the detected drives. The list is sort of random every time, some drives are there and some not on each reboot without touching anything.

I already thought it was one hard drive that was faulty, then I thought it was one SATA cable that was faulty but no. Each time changing hard drives or cables the problem comes back after a while.

Symptoms: (rotating) hard drive drive randomly disappears in Windows or is not detected on boot. Or everything loads extremely slowly (200 times slower than normal speed).

I have 2+6 SATA ports on my motherboard (Asus P9X79 WS). Drives on at least 5 of the ports have been disappearing, but it's probably totally random. Drives show 100% ok in SMART tests (when they are not disappeared).

My C: drive is an SSD drive and so far has not once disappeared but the rotating drives disappear. The computer can work totally normally for 8 hours (under 60°C temperatures) and then suddenly one drive may disappear.

Based on this description, what might be broken?

My guess is that you have a motherboard problem. To test, boot into Linux Live, and work there for a while. See if the same problems exist there. If not, then it's something with Windows. If the problems exist in Linux, then it's a hardware problem. My guess is the motherboard.

Do you have another computer that you can start swapping parts with? For example, if you swap hard drives between the two, you will know right away whether the problem is in the hard drives or in the motherboard. But I doubt it's the hard drives, because more than one drive has been affected by the problem.

You could install a SATA controller card in your computer, which would provide some additional SATA ports. Plug your drives into the new ports, and see if the problem goes away. If it's the motherboard, and if it involves only the SATA ports, then this should fix it. If it does, it will be your easiest and cheapest fix.

Two final things to check: Swap SATA cables between the drives, both the data cables and the power cables. If this has no effect on anything, then you can eliminate the cables as a possible problem.

Thank you for your suggestions!

I think Linux is not necessary because it happens already on the boot sequence or by going directly into BIOS on boot. Sometimes (randomly) drives are missing already there.

I have 8 hard drives so I tried a lot of swapping them already. It seems any of those rotating hard drives are symptomatic. However that suggests to me that the fault is not in any of the hard drives themselves.

The tip about a SATA controller card is great. I didn't know they exist.

SATA power cables I didn't try to swap yet. So yes, the next thing is to swap them and then buy a SATA controller card, thank you!

Very difficult to us to help you as we don't have your hardware specs. Please edit your profile with ALL your hardware specs.

As you changed the CMOS battery, the BIOS was set to the defaults. It may be a wrong SATA configuration. Have a look.

One additional thing that would help me out: has anyone encountered a case where one faulty SATA data cable has caused an adjacent drive to fail (disconnecting a drive while there's nothing wrong with that particular drive's cables)? While the drive with the faulty cable works fine? Both drives connected to the same motherboard.

A bit confusing question but it would help me to know if that's possible. Because that is one possible scenario on my case.

My specs:
- motherboard Asus P9X79 WS
- 6 rotating hard drives (problems with all: WD and Samsung), 2 SSD drives (no problems with these, they are connected to different "SSD Caching" ports – there are two types of SATA ports on the motherboard)
- 8 GB x 8 GB memory (G. Skill RipjawsX DDR3 1600 MHz)
- Intel i7-3930K 3.2GHz LGA2011 processor (with Noctua NH-D14)
- Corsair HX520W power

I'm 99% sure the problem is not the SATA configuration in BIOS. Because regardless of the BIOS configuration, the drives are recognized randomly. There's some other factor causing the problem. (Windows works on both IDE and AHCI mode the same, both have the same problem.)

Open device manager to see if there is any yellow alerts of missing drivers.

jimhoyle said:

The tip about a SATA controller card is great. I didn't know they exist.

Here are several different SATA controller cards:

https://www.amazon.com/s/ref=nb_sb_s...=1Q5LS5OUUIANN

You could get an 8-port card, but they are expensive. A 4-port card is a lot cheaper; however, a 4-port card won't give you enough ports for all your drives. I would suggest that you get a cheap 4-port card and try it. If that fixes the problem, then either get a second 4-port card, or get one 8-port card.

Most of the cards listed at the above link are PCI Express x2. x2 will fit into any PCI Express slot. However, if you have an available x4 or x16 slot, AND if you can find a card that fits that type of slot, you will have a wider data path, which will probably mean faster data transfer for the hard drives.

Some of the cards listed are for PCI, not PCI Express. Unless your computer is old, it is not likely to have a PCI slot. So make sure you pay attention to that detail.

If you can find a SATA controller card at a local store, you might be able to buy it in order to test your computer with it, then bring it back to get a refund or trade up to an 8-port card, so you don't waste any money buying a card you can't later use. In my view, it is better to have only one of these cards in the computer, because in that way you would use only one expansion slot.

Yes, that is great! However, I have to wait now. Because I have now changed two SATA data cables. The old ones didn't look bad but I still changed them. Changing the first one (whose drive got disconnected) didn't help in the long run. But changing another one too (whose drive mostly didn't get disconnected, but sometimes did), that might've actually helped. I've ran it now for two days without problems.

If it was (only) a faulty SATA data cable, I can with certainty say that a broken SATA data cable may affect not only the drive it's attached to, but other drives connected to the same motherboard as well. (Even though they are physically not chained like in the old parallel attachment.)

It seems like every day I learn something new in this business. You have to use your imagination and try different things, especially something as easy as changing a cable, to see if it fixes things. The cable was touching a SATA port and a SATA device, so in my mind, it was a possibility, although a remote one, that it could be the culprit.

Let's keep our fingers crossed. It looks like this one is solved.

Use a contact cleaner on the cables and on MB and HDD socket.
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