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#46464 - 09/27/17 02:42 PM Bizarre problem with Seagate USB 5TB hard drive
tacit Offline


Registered: 08/03/09
Loc: Portland, Oregon, USA
Okay, so here's one for the record books...

My MacBook Pro 15" (TouchBar) has been having intermittent problems accessing WiFi lately, with frequent dropouts, slow Internet performance, "Unable to Connect" messages, and network timeouts.

I've done all the standard troubleshooting--reset SMC, delete network preferences, reset router, and so on--and nothing has helped.

Today, I discovered the cause: a new Seagate 5TB USB hard drive connected via a micro USB-3 to USB C cable.

I use the drive for Time Machine backups, and I've discovered that when the hard drive is connected, I experience network problems and dropouts, but when it is not, I don't.

In fact, I can trigger the network problems by loading a page in Google Chrome or Safari and plugging in the hard drive. When it mounts, the network slows down or drops out completely. When I eject the drive, everything instantly returns to normal.

I have two other USB hard drives, both WD, and a USB C hard drive enclosure with a Samsung SSD inside, and none of these drives causes this problem. But the Seagate? Every time.

This is a bizarre problem I've never encountered before or indeed seen anything like. Anyone ever heard of such a thing? I'm stumped.
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#46469 - 09/28/17 06:46 AM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: tacit]
MacManiac Offline
Moderator

Registered: 08/04/09
Loc: Paradise....on the central Ore...
Just a thought, but isn't your internal WiFi interface USB? Perhaps the Seagate drive isn't playing nice with the USB internals....?
Do you have an intermediate hub in your collection of gizmos that you might be able to plug in between?
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#46472 - 09/28/17 12:20 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: MacManiac]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
I know that on my late 2012 Mac mini and my wife's Late 2014 Mac mini, Bluetooth was handled through USB, so on the more recent Macs with Thunderbolt 3/USB C I would not be surprised to find WiFi being handled on the TB 3/USB C buss. Neither would I be too surprised to find that the Seagate USB USB 3 port or the USB C to USB 3 adaptor cable you are using is a bit wonky. The first thing I would try is a different USB C / USB 3 adaptor.
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#46475 - 09/28/17 03:44 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: joemikeb]
tacit Offline


Registered: 08/03/09
Loc: Portland, Oregon, USA
Indeed, a quick glance at the system report shows that the wifi hardware is connected to USB via an Apple USB bridge. The idea of trying a different USB 3 to USB C adapter is a good one! I will try that next time I'm using that hard drive and see what happens.
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#46489 - 09/29/17 09:38 AM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: tacit]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
also is the drive powered by your computer? maybe you're getting a power brown-out?
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#46498 - 09/29/17 03:57 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: Virtual1]
tacit Offline


Registered: 08/03/09
Loc: Portland, Oregon, USA
Nope, it's a desktop 5TB drive with its own power supply.
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#46582 - 10/07/17 11:46 AM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: tacit]
tacit Offline


Registered: 08/03/09
Loc: Portland, Oregon, USA
So, following up with this:

Changing cables does not solve the problem. It appears the 2016 Macbook Pros may have a design defect: when the USB bus is saturated with high-speed disk I/O, the WiFi may drop out.

The Seagate drive in question is one I've recently turned on encryption for, so it's doing the whole "Encrypting Disk" that takes several days (whole-disk encryption even encrypts free/unused space on the disk). While that encryption is ongoing, there's constant background disk access, and that seems to be what's kicking me off the network.

I have a screaming fast external USB-C SSD that I use for disk clones, and while I'm doing a clone with Carbon Copy Cloner, that can also kick me off the network.

In other words, because the WiFi is connected internally via a USB bridge, saturating the USB bus causes network problems.

For whatever reason, probably dealing with how the bridge is connected, this is much more a problem when I use the left-hand USB ports than when I use the right-hand USB ports on the MBP.
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#46584 - 10/07/17 12:09 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: tacit]
MacManiac Offline
Moderator

Registered: 08/04/09
Loc: Paradise....on the central Ore...
That's kinda what I thought you might find.....the internal USB hardware that serves all such ancillary functions (such as WiFi, and keyboards and trackpads, etc) seamlessly starts to have a tummy ache when saturated by the high volume data capabilities of the USB C / Thunderbolt 3 external interfaces when heavily tasked.

Your testing certainly points in that direction....have you submitted this to Apple yet?
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#46597 - 10/09/17 10:00 AM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: tacit]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: tacit
In other words, because the WiFi is connected internally via a USB bridge, saturating the USB bus causes network problems.

Interesting... reminds me of a related issue - if you attach an apple isight camera at the end of a chain of one or more firewire hard drives, it will occasionally corrupt data running to/from the hard drive.
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#46618 - 10/13/17 11:20 AM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: Virtual1]
tacit Offline


Registered: 08/03/09
Loc: Portland, Oregon, USA
So I've been digging on this problem, and it appears to be a common problem experienced by a lot of other MacBook Pro Touch Bar users, but it is not, in fact, a bus saturation problem.

There are complaints of this exact issue all over the Apple discussion boards, with a majority of people saying the problem stems from RF interference. The USB C ports are so fast, the cables leak radio-frequency interference that collides with WiFi signals. People have had some success by doing things like wrapping their USB cables in rubber or switching to 5GHz wifi.
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#46620 - 10/13/17 01:46 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: tacit]
artie505 Online


Registered: 08/04/09
A while back I asked about chokes on cables, and the explanation I got made it sound like one may be helpful in your situation.
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#46621 - 10/13/17 04:41 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: artie505]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: artie505
A while back I asked about chokes on cables, and the explanation I got made it sound like one may be helpful in your situation.
Maybe, but so far I have not seen a choke on Thunderbolt 3/USB C cable with a choke and that is where the stray RF is supposedly leaking.
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#46622 - 10/13/17 05:09 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: joemikeb]
artie505 Online


Registered: 08/04/09
Originally Posted By: joemikeb
Originally Posted By: artie505
A while back I asked about chokes on cables, and the explanation I got made it sound like one may be helpful in your situation.
Maybe, but so far I have not seen a choke on Thunderbolt 3/USB C cable with a choke and that is where the stray RF is supposedly leaking.

Can't one be improvised?

Unless I'm mistaken, it could be done with iron filings (scavenged from another cable if need be) encased in an appropriate "wrapper".


Edited by artie505 (10/13/17 05:38 PM)
Edit Reason: Generalization
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In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#46623 - 10/13/17 06:45 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: artie505]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
RF Chokes can be surprisingly sophisticated devices and their architecture is dependent on the frequency band you are seeking to suppress. Many years ago Radio Shack used to sell RF chokes you could run your cable through so you might still be able to buy them from an electronics supply store but you still need to know what frequencies(s) you are filtering for optimum effectiveness, and depending on where the leak is occurring even a properly designed and manufactured choke may not have any effect.

RF at these frequencies is freaky stuff and a solution could potentially involve anything from completely re-engineering the plugs and/or sockets, changing the internal architecture of the cables themselves, encapsulating the cable and plugs in a grounded metal braid (like a coaxial cable), shortening or lengthening the cable so that it is not a harmonic wavelength, to (as tacit mentioned) wrapping the cable in another layer of rubber (although rubber is not a good RF insulator so I can't figure out why that could help confused ). I do know that Thunderbolt 3/USB C cables are relatively expensive and the longer they get the bandwidth is often either reduced or the cost goes up disproportionately. This kind of problem is not unique to Thunderbolt 3/USB C it has occurred over and over again as data bandwidths have increased and new connectivity solutions have been developed.

There are a few things I am certain at this stage of TB 3/USB C development.
  • Cheap cables are a bad investment and will too often result in unexpected problems
  • I am reminded the old adage you get what you pay for is still a fact of life.
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#46624 - 10/13/17 06:54 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: joemikeb]
artie505 Online


Registered: 08/04/09
Thanks for both the clarification and the education. (It was a nice idea while it lasted.)

Now that there's a specific "search" area, can anything useful be inferred from the fact that tacit's issue is caused by only one of four drives or, as the case may be, enclosures?


Edited by artie505 (10/14/17 12:38 AM)
Edit Reason: Expand
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The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#46628 - 10/14/17 10:33 AM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: artie505]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: artie505
Now that there's a specific "search" area, can anything useful be inferred from the fact that tacit's issue is caused by only one of four drives or, as the case may be, enclosures?

Tacit is also having problems with another drive in another enclosure...
Originally Posted By: Tacit
I have a screaming fast external USB-C SSD that I use for disk clones, and while I'm doing a clone with Carbon Copy Cloner, that can also kick me off the network.

While that does not rule out enclosure hardware/firmware as a problem source or contributor good troubleshooting technique would move any common elements to the top of the suspect list. In this case that would be his MacBook Pro. Flooding the data channel seems plausible, but given two drives are apparently functioning normally and two are not seems to refute that as a cause.

All of this takes me back several years to the days when Apple was using the PowerPC and system design was pushing hard against the upper end of the DIMM performance envelope. While Apple was using memory built to a defined standard, many DIMMs would not work or would have very high error rates when used in Macintosh computers even though they were ostensively built to the correct standard.

Thunderbolt 3/USB C in the current MBPs is pushing the performance envelope defined in the standard, just as the PowerPC was pushing the DIMM standards in those earlier days, so it would not surprise me to find that some enclosures choke when data speeds are at or near the upper margins of the specification. (Neither would I be surprised if there were multiple issues involved. )

INTERESTING EXPERIMENT: If the RF “leak” is originating in the MBP, moving the drive further from the CPU might reduce the error rate. If the connecting cable is the common ½ Meter (19 inch) switch to a 2 meter (6.6 feet) cable that is 40 Gbps certified and move the drive as far from the MBP as possible and see if the problem reccurs. I would try it, but all my external drives are working satisfactorily. (My only lingering issue is an intermittent sleep/wake crash or kernel panic.)
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#46629 - 10/14/17 11:16 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: joemikeb]
artie505 Online


Registered: 08/04/09
As has been said, it's a wonder that these things work at all, let alone as well as they generally do.

I was wondering whether, in having apparently been stuck on the Seagate as the cause of his problem, tacit was overlooking its enclosure, and your excellent explanation of "the process" suggests that the enclosure may, indeed, be a/the culprit.

On the other hand, though, the full extent of tacit's problem is unknown without his having run all tasks from/on all volumes; the drives/enclosures that haven't choked may not have been pushed to their limits with what they've been asked to do so far.
_________________________
The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#46659 - 10/17/17 12:27 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: joemikeb]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: joemikeb
RF Chokes can be surprisingly sophisticated devices

Amazon has snap-on chokes on the cheap
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#46660 - 10/17/17 12:32 PM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: artie505]
tacit Offline


Registered: 08/03/09
Loc: Portland, Oregon, USA
It's entirely possible the problem is related to high bandwidth data transfer and also to RF leakage, since the cables may be leaking RF interference that only becomes a problem when there's a ton of data traveling through the cable. That is, bandwidth saturation isn't the problem, but it triggers the problem because that's when the RF noise is the worst.

Some folks online who are encountering this problem say that it happens with some cables but not others, while other folks say it happens all the time. So it looks like there are potentially a large number of confounding factors: the cable, the enclosure, the amount of information being passed down the cable (which affects the amount of RF leakage)...

The 2016 MBP doesn't look like a huge change from earlier models, except for the TouchBar, but internally it's very different, and I wonder if the problem is indeed that Apple is pushing the design envelope hard.
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#46678 - 10/22/17 10:32 AM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: tacit]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
A friend was having interference problems with his MBP and it turned out one of his Thunderbolt 3 cables is not certified and although another is certified, it is on certified for 20 Mbps. Switching to a connector cable certified for 40 Mbps solved his interference problem. The TB 3 cable certified at 40 Mbps is significantly larger in diameter, stiffer, and more expensive but there is no interference when using it.

Given my friend's experience, I decided to replace the no brand name ½M TB 3/USB C cable I have been using, because it was cheap, with a 1M cable certified at 40 Mbps and the static we have been experiencing with the cordless phone in our office disappeared. cool
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#46679 - 10/23/17 07:23 AM Re: Bizarre problem with Seagate USB 5TB hard drive [Re: joemikeb]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: joemikeb
A friend was having interference problems with his MBP and it turned out one of his Thunderbolt 3 cables is not certified and although another is certified, it is on certified for 20 Mbps. Switching to a connector cable certified for 40 Mbps solved his interference problem. The TB 3 cable certified at 40 Mbps is significantly larger in diameter, stiffer, and more expensive but there is no interference when using it.

You might want to look at my musings earlier on the subject: https://www.finetunedmac.com/forums/ubbthreads.php?ubb=showflat&Main=6113&Number=45905
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