3 Replies Latest reply: Feb 6, 2014 6:02 PM by tbirdvet
Cartoonguy Level 1 Level 1 (0 points)

I have a USB 3 drive and I notice that when accessing files on my internal drive (that is, not the USB 3 drive) it sometimes needs to wake up.  I hear it whirring up to speed and it takes about 5 seconds while the entire system hangs until it comes online and then everything goes back to normal.  This happens while I am already actively using the system.  Any idea why and how to stop this?


By the way, the drive was in a Lacie enclosure, but I moved it to a new USB3 enclosure myself.  It is listed in Disk Utilities as a SAMSUNG HD204UI.  It's 2TB and 7200rpm.  I also have a WD drive in another USB3 enclosure as a Time Machine backup.  It doesn't seem to be causing the issue.

iMac, OS X Mavericks (10.9.1), 3.4 GHz, Fusion drive
  • tbirdvet Level 4 Level 4 (2,800 points)

    This is typical.  My drives do the same and it will hang your system up until it spools up.  If you find you do not like this try setting "do not sleep" however with Mavericks this does not always work.  You can also use FW drive which will not sleep no matter what is set (another Maverick bug) but will sleep when Mac shuts down (USB3 will not).

  • Cartoonguy Level 1 Level 1 (0 points)

    Didn't know that this was a feature of USB specifically.  I actually took my drives out of FW enclosures and moved them to USB3 since that's so much faster.  When you refer to the do not sleep setting, I guess you mean in the Energy Savings settings where you have the tick box to "Put hard disks to sleep when possible".  I unticked that and it seems to be helping, so far!

  • tbirdvet Level 4 Level 4 (2,800 points)

    That is not a USB feature it is something to do with the OS not being correct.  You are correct in unchecking the box in the energy pane and see if this keeps the drive from sleeping which will get rid of the system lag.