CF/SD card readers suddenly disconnect/drop out when I plug in other USB devices

Question

CF/SD card readers suddenly disconnect/drop out when I plug in other USB devices

I have two CF/SD card readers from two different manufacturers (both are on the cheap side, though).

Whenever either one is connected to USB, when I plug in a different USB device (like a HDD, a pendrive or such), the reader suddenly quits (drops out).

This happens only if there is anything in the reader to begin with (ie. a card is present and mounted). Otherwise, no transfer needs to be in progress.

I can reproduce this with about 95% success rate:

a) plug a CF or SD card into one of the readers

b) have the Mac recognize the card and mount it

c) plug in a USB HDD or some similar device (yes! it can be the second card reader, but then the reproducibility drops to about 60-65%)

Immediate effect: the CF/SD card is dropped (the USB reader 'goes dark' as if physically unplugged), and an error message about "unmounting volumes first" appears on screen (followed by "some files can't be read" and failures, if there were any data transfers going on).

Before resuming operation, the device must be physically unplugged and plugged back in.

Other USB devices I own are not afflicted by this. This is a constant problem, and it has been happening for the past three years (ie. as long as our company has owned the machine). The machine shipped with OSX 10.6.5 I believe, and it has been constantly updated until version 10.6.8 at present time.

I am pretty sure it's neither the USB cable (tried several, from different shops and manufacturers, certified USB 2.0 and not) nor the physical port/location on the Mac (also tried all possible combinations over the years). Needless to say, we're still suffering the symptoms. In fact, I'm posting this precisely because I got fed up when it happend about an hour ago.

The CF/SD readers used to have a lot of problems with nearby cellphones (incoming call/text caused the same symptoms) until we switched to proper USB cables. Nowadays this only happens if the phone is REALLY close to the CF/SD reader (within 15cm or so). I assume this to be a separate problem altogether (I have confirmed that neither reader has any sort of EM protection, nor did I expect them to), and one already adequately solved.

I strongly suspect that a more pricey CF/SD reader will "solve" this problem, but I'm posting here just in case.

Thoughts?

Mac Pro (Mid 2010), Mac OS X (10.6.8)

Posted on Sep 9, 2013 2:37 AM

Reply

Answer 1

ezylstra

Level 1

15 points

Sep 9, 2013 10:28 AM in response to Michal_Ellmann

This sounds like a driver issue. Which CF/SF card readers? They aren't handling additional devices on the USB bus (obviously).

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Answer 2

Sep 10, 2013 12:32 AM in response to ezylstra

The interesting thing is: after they're reconnected, no further problems show up. So they're handling devices just fine, with the itty-bitty exception of the connection moment.

As to models, it's an "eneride" ("made for Top 3 GmbH & Co. KG") and a no-brand no-name (seriously, all that is on the box is instructions!). Like I said, cheap.

As I've mentioned, it's most likely the readers themselves (for no-brands or not-from-brandnames-I've-heard-of-before I didn't expect much). I just posted to see if maybe there existed a bigger USB-related problem that manifested itself this way.

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Answer 3

aemer

Level 1

0 points

Jan 4, 2014 5:04 AM in response to Michal_Ellmann

Hi Michal,

do you solve the problem ?

In my Macbook Air 2012 I have same problems ... I bought an 64Gb SD card ( Sandisk extreme UHC1 ) to use it as secondary HDD ( some ) but whenever I connect an external HDD ( USB 2 or 3 ) the SD memory is dropped and the message "unmounting volumes first" appears.

I check with differts sd card ( 64Gb - 32Gb and 8Gb ) and differents USB HDD but I received same error.

Only with "usb pen drive" all works fine.

Tuesday I'll open a ticket to customer care ....

Alessandro

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Answer 4

Jan 4, 2014 8:58 AM in response to Michal_Ellmann

The limited amount of USB Bus Power can cause all sorts of problems for Bus-powered devices. I recommend you get power supplies for all that can be powered that way for best stability.

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Answer 5

aemer

Level 1

0 points

Jan 4, 2014 1:13 PM in response to Grant Bennet-Alder

Thanks for your reply Grant.

My macbook air is an high level PC and I don't accept this type of problems ...

My daughter uses every day an old vaio pc without this problems ..... possible ?

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Answer 6

Jan 4, 2014 1:17 PM in response to aemer

Then you should explain your displeasure to AppleCare on the telephone, or make an appointment at the Genius bar and explain it to them.

I expect they will tell you that Apple brand peripherals do not cheat on power requirements the way your Brand-X devices do, so they do not have such problems.

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