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new 27" iMac, USB3 troubles

1147 Views 10 Replies Latest reply: Feb 7, 2014 7:51 AM by F.Lateralis RSS
dandig Level 1 Level 1 (15 points)
Currently Being Moderated
Jan 23, 2013 9:37 AM

I have a new iMac and weird things have happened with the USB3 ports since day one.  At the moment I have a USpeed 4-port USB3 hub and when the iMac starts up, the hub goes onto the USB2 bus, not USB3.  To get it to show up on the USB3 bus you have to pull the power from the hub and plug it back in again.  It has to be the power , simply pulling the USB plug and putting that back in does not work.


At first it sounds like a bad hub , but the exact same thing was happening with another set of things plugged in before I even got the hub.  When I first started up the computer I plugged in an older wired USB Apple keyboard ( the one that has a USB hub built into it) and that seemed to cause ALL other USB devices which were plugged directly into the iMac ( not into the hub of course) to go onto the USB2 bus and not the USB 3 one.


There has to be a link between these two problems.... but they are both slightly different.

iMac, OS X Mountain Lion (10.8.2), 27" 3.4GhZ
  • Baby Boomer (USofA) Level 9 Level 9 (55,540 points)
    Currently Being Moderated
    Jan 23, 2013 11:12 AM (in response to dandig)

    Call AppleCare ASAP!!!!!!!


    You should not be troubleshooting a spanking brand new out of the box computer.


    Take full advantage of your warranty. You have 14 days from the date of purchase to exchange and/or return with no questions asked!


    You also have 90 days of FREE phone tech support.




































    MacBook Pro, Mac OS X (10.6.8), Original MBP (2/2008)
  • Chessie 01 Level 1 Level 1 (85 points)
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    Jan 23, 2013 11:51 AM (in response to dandig)

    In addition, I recommend that you purchase Apple Care.  You can do so during the 1 year warranty period.  It offers you 3 years of free phone tech support and it extends your basic warranty. 

  • LownoteNB Level 1 Level 1 (0 points)
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    Jan 29, 2013 1:28 PM (in response to dandig)

    This is slightly off topic but I'm scheduled to get my new iMac on Feb 5, and I have most of what I need in hand to make a quick transition from a 3-year old iMac.  I would appreciate knowing about your experience.  My ancient Belkin USB 2 hub is starting to get flakey and I thought I would purchase a new USB 3 hub to replace it.  However, I'm seeing warnings that wireless devices like my MagicPad may not work with the USpeed USB 3 hub that you own. Have you had any problems with your wireless devices when the hub is in operation or devices working at USB 3 speed when plugged into your hub?  In addition to some older USB devices that I want to plug into the new hub (Epson printer, Focusrite audio interface, Mac extended keyboard, video card reader), I would also like to plug in a powered 3TB Seagate USB 3 external HD that I'm going to use as a TM backup. Main data storage will be on new Thunderbolt Drobo. Thanks. 

  • LownoteNB Level 1 Level 1 (0 points)
    Currently Being Moderated
    Jan 29, 2013 2:49 PM (in response to dandig)

    The comments came from several Amazon hub listings--both the product descriptions and the user reviews, some of which appear to be written by tech-savvy users.  Evidently the chipset in your hub is used by several manufacturers.  Here dips one review that saw. r_1_1?s=computers&ie=UTF8&qid=1359498581&sr=1-1


    Here is another review that caused me to write to you


  • William Donelson Level 4 Level 4 (2,495 points)
    Currently Being Moderated
    Jan 8, 2014 6:41 AM (in response to LownoteNB)

    USB3 radiates the same frequencies used by WiFi and many wireless products.


    In my experience, not a single USB3 hub is reliable due to stupidity of USB3 design.


    AVOID USB3 and if you must use it, use short BEST QUALITY cables, heavily shielded. USB3 has caused repeated trouble in our offices.

  • F.Lateralis Calculating status...
    Currently Being Moderated
    Feb 7, 2014 7:51 AM (in response to dandig)

    Does anybody has a solution yet?


    It looks I have the same problem on my iMac 27"",  just bought.

    - Cannot format (with disk utility) a USB 3 external harddisk (WD red 2TB harddisk in a USB 3 case), connected to the USB 3 port, however could format via the Apple-keyboard (USB 2) that is connected to USB3.

    - Looses connection while performing a backup (using backup tool  Synchronise) connected on USB3. While USB 2 no problem, but terrible slow.


    However, I don't have any connectionproblems with my "WD MyBook 4 TB harddrive", which was pre-formatted by WD.


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