7 Replies Latest reply: Aug 23, 2012 9:55 AM by hani7up
hani7up Level 1 (20 points)

I am using a new iMAC and in general terms I am quite happy with it. However, I have connected to it, through a D-Link 4 port hub, with external power source, two USB HD, both of which being 1TB each, an Iomega with its own power source and a Toshiba, which has a double pronged usb cable, one of which is to draw the extra needed power to run this HD (if and when required). As I said, both are connected to a D Link hub, which in turn is connected to one of the rear USB ports in my iMAC.


However, at startup, I sometimes discover that the iMac did not detect the HD, although both iMAC and the hub in question are connected to the same power source distribuitor.


Does this mean that the USB port is mal functioning? Do I need any special upgrade software (although Software Upgrade says all is in order), or is it the D link? I get over the problem by disconnecting the D Link USB cable from the rear of the iMAC and plugging it again to the same USB rear port.


Would you guys recommend a different setting?


Thank you in advance for your help.

iMac, Mac OS X (10.7.2)
  • RRFS Level 5 (4,490 points)

    Is your iMac not seeing both of the hard drives? Will your iMac see the drives if they are directly plugged into it?

  • hani7up Level 1 (20 points)

    I didn't actually try this because while waiting for an answer from the Group, I did a Google searched and discovered I had to update my iMac's Efi and SMC firmware, which the normal day to day Software Update sometimes ignores. I found an update, installed it and restarted my comouter around 10 times and the result was good. The HD always appeared connected. It seemed the upgrade fixed a bug that had to do precisely with this issue among another couple of tweeks.


    Thanks for your help anyway, and in case the problem occurs again, I'll give you suggestion a try. I assume your question would solve the issue of the efficiency of the Hub.


    Cheers! :)

  • BDAqua Level 10 (122,237 points)

    Great work, thanks for the report!

  • hani7up Level 1 (20 points)

    I am afraid I have bad news...


    Updating the EFI and SMC firmware of my iMAC did not solve the issue. I have just arrived home, at 00:30, eager to send an important business email. I switched on my computer and surprise, surprise,... none of the USB HD appear on the desktop. In other words, we're back to square one.


    It's too late to start tinkering away now. I will try to follow RRFS's advice and connect the 2 HDs directly to the rear ports and will see what happens.


    I'll keep you informed.

  • luisyalmu Level 1 (0 points)

    I have a simillar problem with my WD external HD (1TB) connected directly to the USB port. OS is 10.6.x (the latests 10.6), not always hapend, but some times. I have another HD conected by Firewire for the time machine task, no problem with it. I´m thinking to move to the 10.8.x OS, but i dónt know if it will be resolved.


    Tested the same HD in other MAC (Mac book) with a 10.7.x OS, it works fine.



  • BDAqua Level 10 (122,237 points)

    Hi Luis, I'd wait on 10.8, or at least investigate all the new problems with it first.

  • hani7up Level 1 (20 points)

    Just to keep yu guys posted, both USB HDs are directly connected now to the rear USB ports and so far so good, no disconnection, no monkey business. It's not the set up I thought I'd use, but will keep it for the time being till I get a solution and get to use my HUB for those 2 HD without any indicences.