Question USB devices "flapping" during disk activity.

dave_the_nerd · Apr 26, 2025

I have a powered USB 3 hub, AC adapter is plugged in. Have a USB DVDRW attached. Was working fine. DVD drive also has its own external PSU, but I can hear it "click" when just the USB is plugged in so I think it gets power from both.

Attached an external HDD. 3.5" 4TB. Also has its own PSU. Plugged it into the same hub and formatted it. So far so good. Connected with a USB2 cable (another USB 3 cable is in the mail) so transfers are slow, but I'm not sure that matters?

Now when I read/write data on the HDD, I hear the computer constantly making the "USB device inserted/remove" noise, and I can see the DVD drive disappearing and reappearing in the device manager and This PC windows.

I looked around in the Event Viewer, but don't see any obvious errors or reasons. And I went through the Device Manager and unchecked the "Allow computer to turn this device off" option in the power management tab of all the USB devices that had it. Neither effected anything.

The "Events" tab for the DVD drive, in the device manager, also shows no events since the initial attachment and driver installation.

I also tried a different hub and a different power adapter for the hub, and have the same issue. Nothing else plugged into the except the DVD and HDD; again, same problem.

Any ideas about where I should look for a cause?

mikeymikec · Apr 26, 2025

My first guess is that it's a USB compatibility issue. Does the DVD drive work perfectly while connected to that hub without the 4TB drive connected?

Two different hubs or are they the same model?

dave_the_nerd · Apr 26, 2025

mikeymikec said:
My first guess is that it's a USB compatibility issue. Does the DVD drive work perfectly while connected to that hub without the 4TB drive connected?

Two different hubs or are they the same model?

The DVD works fine by itself, yes.

Two different hubs, different models but both USB 3. (One Amazon basics the other some weird store brand I bought on eBay a million years ago. I don’t like it because it’s got bright lights on it.)

dave_the_nerd · Apr 26, 2025

Well... that's weird. I got the package with the new USB 3 cable, replaced the USB2 cable, and it's working fine now.

::throws USB2 cable in the trash::

I'm not sure how/why the HDD's cable would be able to disconnect the DVD drive (unless data errors were causing the hub to disconnect or reset?) but I'm not one to turn down a solution.

Also, it's been a while since I used a computer with a 3.5" HDD. They're not fast, but seeing this one push 190MB/sec writes is.... actually pretty impressive?

mikeymikec · Apr 26, 2025

dave_the_nerd said:
Well... that's weird. I got the package with the new USB 3 cable, replaced the USB2 cable, and it's working fine now.

::throws USB2 cable in the trash::

I'm not sure how/why the HDD's cable would be able to disconnect the DVD drive (unless data errors were causing the hub to disconnect or reset?) but I'm not one to turn down a solution.

In the last year I've experienced a spate of USB2 A-B cables dying of apparent old age.

dave_the_nerd said:
Also, it's been a while since I used a computer with a 3.5" HDD. They're not fast, but seeing this one push 190MB/sec writes is.... actually pretty impressive?

The Seagate Ironwolf NAS 4TB drive in my PC pushes a peak of >200MB/sec. I really should have benched the couple of 8TB drives I've rolled out in the last few years to customers (but maybe they just have more platters).

If it wasn't for me wanting a near-silent PC and higher capacity drives being more noisy and that this case very awkwardly mounts 3.5" drives, this 4TB drive's successor would have been a HDD. It's easily enough performance for random media storage.

Jimminy · Apr 26, 2025

Never trust any USB cable, even if it was an expensive brand named item.

USB 2 or lower is fairly forgiving, but anything above that speed, I always suspect the cable first.

pcswig13 · Friday at 11:23 AM

I just found this thread and it addresses a very similar problem I am having. I have a slightly used and reformatted Crucial 480gb SSD that I put into a USB3 enclosure (purchased from Newegg). I have used it several times over the last few weeks without issue, as late as yesterday afternoon. Then this morning when I plugged it in to my tower PC, it started this "here/not-here" cycle and it would not stabilize where I could use it. I read this thread, changed the cable (a USB3 with the dual style connector at the drive end) for another identical cable, and Bam! It works fine. I guess the other cable is the problem, even though it is only a few months old.
Could this also be related to different BIOS's - yesterday I used it on a computer at the office with no issues and today connecting to my home computer is when the problems began.

Jimminy · Friday at 3:17 PM

pcswig13 said:
I just found this thread and it addresses a very similar problem I am having. I have a slightly used and reformatted Crucial 480gb SSD that I put into a USB3 enclosure (purchased from Newegg). I have used it several times over the last few weeks without issue, as late as yesterday afternoon. Then this morning when I plugged it in to my tower PC, it started this "here/not-here" cycle and it would not stabilize where I could use it. I read this thread, changed the cable (a USB3 with the dual style connector at the drive end) for another identical cable, and Bam! It works fine. I guess the other cable is the problem, even though it is only a few months old.
Could this also be related to different BIOS's - yesterday I used it on a computer at the office with no issues and today connecting to my home computer is when the problems began.

I've had brand new cables be faulty, right out of the package. Sometimes they exhibit strange behaviors as well.

When buying, look for the thickest and most robust built cables. I avoid the real skinny super flexible types, though I've have a couple of them last a pretty good while.

I always suspect the cable first, and about 9 times out of 10, it turns out to be the culprit.

mikeymikec · Friday at 3:26 PM

I bought a pair of USB3-HDD (USB 3.0 micro-B I think is its technical name) cables off Amazon (a 2-pack, 1M + 2M), one was obviously intermittently faulty from day one, the other has continued working since I bought it (Nov 2023).

The other thing to watch out for is are you trying to run a USB 3.0 or later device from a 'front USB' port (the type that the case comes with and are connected to the motherboard via cables). I wish I knew how to definitely know which cases have this problem, because my current case (Fractal Design Focus G) has never had any USB 3.0 connection issues, yet I've built many PCs that did on the front ports.

mindless1 · 2025-06-14T22:19:24-0400

I have one system with a bay mount pair of USB3 ports. Over time, the port I used more often developed weak contacts in it, and it works fine with one USB flash drive, but not with another that I'd used on it for years. Same USB flash drive works fine in the other port right next to it, that has been used far less often.

The conclusion is that this particular USB flash drive has contacts on a plug slug that is slightly thinner than spec, and once the port contacts get less spring tension in them, it makes an intermittent connection. Sometimes it shows that "this device could perform faster" message, then if I unplug and replug it a few times, eventually the message goes away and it operates in USB3 mode on the questionable port.

The next time I have that system open for servicing, I'll take the bay tray with that USB port out and bend more tension in the contacts with a dental pick.

Question USB devices "flapping" during disk activity.

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