Mac time machine drive dock sleep question

Plugable U3 drive dock with Mac mini as time machine backup
The drive seems to be running non stop, except when the computer is in sleep mode - even when the backup is finished and not running. When the computer was turned back on, I had to cycle power for it to be recognized by time machine.
How can I get the drive to sleep and wake automatically?

Hi - Thanks for posting!

Unfortunately with power management, there are a lot of layers involved, and if any layer isn’t cooperating, that can keep the drive awake.

At the highest level, the power switch on the dock can be useful if your time machine backups are infrequent. So that’s one (blunt) workaround.

Another trick people often use on Mac OS X is to unmount the partition when the drive is not in use. See…

In that thread, there are also scripts to (partially) automate that from software.

But we’re also researching more automated solutions, and will post back here when we have more. Please feel free to ping us if the workarounds aren’t serving you, and you haven’t heard back yet!


Thanks for the quick response!
I have to admit that most of that was over my head, but the following quote from that post has me wondering -
"It seems the “Put hard disk(s) to sleep when possible” option only puts internal disks to sleep if the whole controller is idle? I have used this option successfully on MacBook’s with only one drive and on multiple external USB and firewire drives (as long as the drive is in the Spotlight Privacy list). "

My question/concern is actually two part;

  1. My biggest concern is why didn’t the drive wake up after the computer restarted from sleep? Time machine was waiting to run a backup “as soon as the drive is reconnected”. It was connected and the switch was on, but I had to cycle it for the computer to see it.
  2. I’d like the drive to sleep as often as reasonably possible, and it seems by the statement above that this should be possible with a USB drive using the ‘put HD’s to sleep’ check box, but didn’t seem to be working.

The drive is shutting down or sleeping, I assume when the computer’s drive sleeps. I have the computer set to not sleep, but for the drives to sleep when possible.
The drive is not waking up though, and that is a problem for automated backups. Not working. help please.

Sorry, that’s got to be frustrating - not waking is definitely a problem!

I haven’t seen this on the Mac here, and we haven’t had other reports of it, but I’ll try to see if we can recreate it so we can figure out what setting, etc. may be triggering it.

Quick question: Is the icon for the drive still on your desktop after sleep, so that clicking on it re-establishes a connection (wakes the drive) or does it take a full unplug/replug to wake the drive?

Sorry you’re not yet at a good time machine setup - we’ll get you there. Thanks for your patience!


No icon. The light on front of the dock is on but the drive is not spinning. The drive does not show up in finder or desktop until I switch it off and back on. Then it spins up, an icon spears on desktop, and both finder and time machine see it automatically.

Thanks! Give us a few days to investigate alternatives, and ping here if we’re slow on the reply. Thanks for your patience!

Any updates or ideas?

Sorry, we’re still researching and don’t yet have any ideas on this one. Because there should be nothing unusual happening with this config, we’re still hopeful that a settings change or something simple will provide a solution, but can’t be sure yet.

This issue is dragging out too long, and we don’t want you stuck with hardware that isn’t meeting your need. If you’re getting nervous and don’t want to wait it out, we totally understand. We have no-hassle returns through Amazon in the first 30 days, just visit… and after the 30 days, just email and we’ll take care of you (we’ll just ask for your Amazon order number and a link here to the public support thread).

Sorry for the long delay, and thanks for your patience to this point while we’ve been researching!


There is a possibility that a newer firmware version may help. We would like to have you check the Plugable’s U3 dock firmware for us.

To do this on a Mac follow these steps:

  1. Click on ‘Applications’
  2. Click on ‘Utilities’
  3. Click on ‘Terminal’.

In the terminal window that comes up, type:

system\_profiler SPUSBDataType   

The result will most likely be pretty long as this will list all the details of all your system’s USB attached devices. Scroll up till you see an entry like this:


Can you please copy the firmware version number here? There is a possibility that all you need is to update your firmware version, but no matter what we’ll keep working on this till we find a solution!

Thanks for being so patient while we’re researching this!


Firmwarecwas the first thing I had thought of…
I have version 22.47
Is that the correct one?


Unfortunately, as we’ve been testing here we’ve not been able to recreate the problem with any of the firmware versions out there for our U3 (there are only two: 22.47 and 24.47), so it’s looking like a firmware change may not be a help.

In our offices we have a MacBook with OS X version 10.6.7. We have tried the U3 on this machine successfully with both versions 22.47 and 24.47. In both cases the hard drive stops spinning in sleep mode and resumes spinning when the computer comes out of the sleep mode.The hard drive we’re testing with here is a 2TB Western Digital 5400 rpm.

So it looks like we need to go deeper to find out what might be different between these two systems. If this is too much, please let us know - a refund is no problem if digging in here becomes too time-consuming.

Would you be willing to give us some more information on your Mac Mini ?

  • Processor and speed

  • Hard Drive make and model

  • Mac OS X version

We know you have a USB 2.0 host controller (OS X doesn’t have USB 3.0 support today), but are you using the USB3 cable or the USB2 cable?

We are sorry we haven’t yet found the root cause here. Thanks for your patience.


I thought maybe you touched on something with the. It was connected with a funny looking cable that came with the unit… I suppose that is the USB3. I swapped it to a more normal looking USB cable, presumably the USB2.
Drive goes to sleep, but is unable to wake up. No difference as far as I can tell.
It’s a new model Mac mini 2.4GHz IntelCore 2 Duo
Mac OS 10.6.7
Western Digital1TB WD10EALS

I’d like to give you a little more time to resolve the issue before I return for a refund.It seems like a good product and I’m not sure what I would replace it with.


Thank for you being so patient. We would like to assure you that we are still investigating this issue.

Further research shows that some times the USB external drives just fail to automatically mount. If this is the case, it’s a problem that should be fairly easy to solve.

At this point we would like to check the following:

When the Mac wakes up from sleep, and the drive does not come up on the Desktop as expected, what do you see in the Disk Utility?
To access the Disk Utility:

Click on ‘Applications’->‘Utilities’->‘Disk Utility’. You should see something like the following screenshot:

If you do see the drive, what options do you see when right clicking it?

Some links that may be of interest:


The drive doesn’t show up at all.

Link 1 makes it seem that if it supported firewire it might work without a hitch. Firewire isn’t supported with the docking station is it?
That script in link2 is interesting. It’s over my head I I but I’ll try it when able.must have gotten something wrong with it because it gave me a bad command error. I’ll try again when able.


We’re still looking into this and researching possible workarounds.

At this point, may we suggest you try to update the firmware of the device (Unfortunately only possible on a Windows machine). Instructions on how to do that can be found here.

Also, when the Mac wakes up from sleep, and the drive does not come up on the Desktop as expected, what do you see when you click the Apple icon ->‘About This Mac’->‘More Info…’->'Under ‘Contents’ click on ‘USB’->Is the ‘MassStorage Device’ visible there ? This is different from the Disk Utility in that it looks for the USB devices on a lower level.

You should be seeing something like this, even with the drive not mounted:



This is what comes up there:

Product ID: 0x5000
Vendor ID: 0x1759 (LucidPort Technology, Inc.)
Version: 22.47
Serial Number: WD-WCATR…
Speed: Up to 480 Mb/sec
Manufacturer: USB 3.0
Location ID: 0x26200000
Current Available (mA): 500
Current Required (mA): 2

After I cycle the power on the dock to remount it, this is what I see…

MassStorage Device:

Capacity: 1 TB (1,000,204,869,120 bytes)
Removable Media: Yes
Detachable Drive: Yes
BSD Name: disk4
Product ID: 0x5000
Vendor ID: 0x1759 (LucidPort Technology, Inc.)
Version: 22.47
Serial Number: WD-WCATR1…
Speed: Up to 480 Mb/sec
Manufacturer: USB 3.0
Location ID: 0x26200000
Current Available (mA): 500
Current Required (mA): 2
Partition Map Type: GPT (GUID Partition Table)
S.M.A.R.T. status: Not Supported
Capacity: 209.7 MB (209,715,200 bytes)
Writable: Yes
BSD Name: disk4s1
Capacity: 999.86 GB (999,860,895,744 bytes)
Available: 863.22 GB (863,215,325,184 bytes)
Writable: Yes
File System: Journaled HFS+
BSD Name: disk4s2
Mount Point: /Volumes/Backup

I have not taken it to a windows machine yet to reinstall the firmware… I’ll try to do that over the weekend.