External hard drive disconnecting on sleep

[starswept]

I recently purchased a June 2013 MacBook Air running Mountain Lion. Around the same time, I purchased a 1 TB Seagate external hard drive, which I partitioned into a section to use for routine back-ups with Time Machine, and a section for extra storage. It connects via USB to the MBA. The hard drive works fine, except for the fact that almost every time I put my computer to sleep, when I open it back up, I get the ominous warning message informing me that the external hard drive was improperly unplugged without first ejecting it, damage may occur, etc. When I look in Finder, indeed the hard drive is no longer mounted, even though it is actually still plugged in. I then have to unplug the hard drive and replug in order for the drive to mount again.

Is there some setting that I can change to stop the hard drive from disconnecting whenever the computer sleeps? The only other alternative I see is somehow make myself remember to eject the hard drive before I close the lid of the MBA every single time I do it, unplug it, and then replug when I start it back up, which is a huge pain given that it is a portable computer that I use all day in various settings. Any help would be much appreciated!

 

[Bruno09]

Hi,

is your external hard drive connected to the MBA via one, or two USB ports ?
(I assume it does not have its own power supply).

I mean do you use a "Y" USB cable ?

 

[starswept]

Hi,

is your external hard drive connected via one, or two USB ports ?

I mean do you use a "Y" USB cable ?

Thanks for your reply. No, I do not use a Y USB cable. It is connected to the MBA via one USB port. This is the exact model of the hard drive if this helps at all, it isn't anything fancy: http://www.seagate.com/external-hard-drives/portable-hard-drives/standard/backup-plus/

 

[Bruno09]

I must say that I have never used a USB 3 hard drive, all mine are USB 2.

Some external hard drives need more current than a sole USB 2 port can supply, i.e 700 mA vs 500 mA, especially when the drive starts after sleep.

In that case, plugging the HD via one USB port only will cause the issue you describe.

Using a "Y" cable solves the problem, because both USB ports feed the HD.

I suppose you have a USB 3 cable and can't test with a Y USB 2.
Otherwise I would have tried with a Y cable and see what happens.

 

[starswept]

I must say that I have never used a USB 3 hard drive, all mines are USB 2.

Some external hard drives need more current than a sole USB 2 port can supply, i.e 700 mA vs 500 mA, especially when the drive starts after sleep.

In that case, plugging the HD via one USB port only will cause the issue you describe.

Using a "Y" cable solves the problem, because both USB ports feed the HD.

I suppose you have a USB 3 cable and can't test with a Y USB 2.
Otherwise I would have tried with a Y cable and see what happens.

Yes, unfortunately I don't have a Y cable. Also, I'm not familiar with them but based on pictures I'm seeing of Y cables on Google, I'm not sure if it would work on my MBA, as it has one USB port on the left side of the computer and one on the right, quite far apart, and I use the left USB port for my wireless mouse receiver and the right for the hard drive.

 

[Bruno09]

I see what you mean.

Some Y USB cable have a long wire between the 2 USB plugs, and would fit your MBA (I do have one if these cables, but USB 2).
http://www.bixmart.com/USB-Y-Cable-2-Type-A-to-1-Mini-5_p_25.html

Or you could use something like this :
http://phcable.en.alibaba.com/produ...mini_usb_y_cable_3_0_20P_Double_AF_cable.html

But anyway if you use one port for your wireless mouse, you have only one port available.

May be somebody else will have other suggestions...

 

[Montychap]

I've the DiskUtility icon on the desktop and use 'Mount' or 'Eject' to control the external hard drive.