Any Problem Using Two External USB-Powered HDDs on rMBP?

Started Mar 29, 2013 | Discussions thread
James A. Senior Member • Posts: 1,248
Fixed my problem with my Retina Macbook and USB 3 drive.

So I have made some head way regarding this odd problem. Turns out my memory card reader is fine I think. My memory card reader will eject on the right port using a 4GB Lexar 133X professional CF card but NOT on the left USB port. However ALL 3 of my sandisk CF cards work fine in the reader on both USB ports. These 3 cards range from all different speeds from 15MB/sex to 30MB/sec. My lexar is 20MB/sec rated. Go figure!?

As for the Western Digital My passport USB 3.0 drive I have come to the conclusion its the drive and not the port. Reading through various forums on Anandtech, Apple Support and the Western Digital website forum many people have had issues with these drives on USB 3 ports on both Windows and on the Mac.



EDIT: I picked up a 1TB seagate USB 3 portable drive the other day and it has worked flawlessly on both ports for large transfers. My lexar USB3 thumb drive also works flawlessly on both ports. I stopped using my Lexar 4GB Compact flash card due to the issue of it being dismounted. That issue has been a problem for other people over at dpreview. I have placed a link to that as well below.


I did notice that my Seagate uses less power than my Western Digital portable drive. The WD drive is said to be using 224ma where the Seagate is only using 36ma. Big difference but I'm not sure how much of that is the factor to this issue. Some people have fixed their WD portable drive by rolling back USB drivers for their motherboard which is something you can't do with a notebook really. My WD drive was really bad in bootcamp via Windows 7 though. It would disconnect every 2 seconds. However no issues in either operating system with the Seagate drive.

My guess is that the right port doesn't supply the same amount of power as the left port on the Macbook Pro considering my WD drive is fine on the left port but not the right port. Though I'm not 100% sure on that as other people have had similar issues with a desktop with this drive on all ports. Hopefully my findings will help someone out on this.

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