USB 3.0 device connecting into USB 2.0 iMac ports

USB 3.0 device not recognized: My 2011 iMac has 4 USB 2.0 ports. I bought an external WD My Passport for iMac USB 3.0 external drive. It is not recognized by the iMac. The WD device works - I plugged it into a friend’s newer MacBook Pro and it worked in both USB 2.0 and USB 3.0 ports and on a newish iMac (forgot to check the vintage). How do I get backwards compatibility so I can connect the WD USB 3.0 device to the iMac USB 2.0 port?

Data: OS is current at El Cap 10.11.6. iMac ( 21.5", Mid 2011) I updated the DW Drive Utilities Installer but that did not help.

iMac, OS X El Capitan (10.11.6), WD My Passport for iMac USB 3.0

Posted on Aug 26, 2016 8:53 AM

21 replies

dialabrain

Level 10

136,127 points

Aug 26, 2016 10:37 AM in response to seagreen939

When you tested the drive in other ports, did you have other USB devices plugged in? If so, you may want to test it with nothing else plugged in.

FWIW, I have a 2TB My Passport and my 2015 MacBook can power it while on battery power. I'm not sure what to think other than not enough power is getting to it.

seagreen939 Author

Level 1

17 points

Aug 26, 2016 10:55 AM in response to dialabrain

I did disconnect all other devices from the other USB ports since this was recommended in other forum posts.

I think the 2011 iMac USB 2.0 power may be the issue, but I have just looked at USB Hubs, and the only things that I can find are USB Hubs that are specifically for CHARGING multiple devices. Isn't what I need more of a USB "router"? I need to connect my iMac to the (intermediate device) which then connects to the external drive. The goal is to write files to the external drive, so whatever (intermediate device) is attached needs to be recognized as an external drive by my iMac.

It appears that I may have just bought the wrong device, and there may not be a realistic fix. (that is, less expensive than just buying another external drive).

rkaufmann87

Level 10

148,494 points

Aug 26, 2016 10:56 AM in response to seagreen939

seagreen939 wrote:

Thanks, I will find a USB Hub and try that. The iMac is a 2011 vintage so the lack of power may very well be the problem since the drive does work elsewhere. The drive doesn't have an option to plug in a remote power source, so the hub may be the only option. Hopefully it won't cost me a lot to find one.

Your welcome and sorry I was a little thick picking up your original point. I also have a 2011 iMac and yup, I think if you use a good quality powered USB hub your drive should work okay.

dialabrain

Level 10

136,127 points

Aug 26, 2016 11:01 AM in response to seagreen939

FWIW, Amazon has a ton of Powered USB hubs, some with charging ports and some without. They start around $10.

seagreen939 Author

Level 1

17 points

Aug 26, 2016 11:12 AM in response to dialabrain

Thanks, I think I have one around here somewhere purchased for travel for powering the iPhones etc. I'll start with that when I can find it!

HibsMax

Level 1

4 points

Dec 21, 2016 1:22 PM in response to seagreen939

I think I have a very similar issue. I have a 2009 iMac running the latest version of Sierra. I bought a 8Tb WD MyBook to use for data and backups (6Tb data, 2Gb backups). It's an external HDD and after I formatted it everything was working as expected. Time Machine was backing up my iMac and I was able to write to that disk. The iMac is on all the time but is not used every day. Sometimes when I go to it there is an error from Time Machine saying that the backup failed. I also get an error code -50 but I don't recall the exact error message. Once I get that error message there is nothing I can do with the drive. I can't backup, I can't manually write, I can't access it via Disk Utility (like to erase) because it says the drive is in use. Then I reboot and everything works as expected again. I contacted Apple support last night and they were friendly but had no answer for me. They didn't even know what -50 meant (I think it's actually a WD error). Anyway, my iMac has USB 2.0 ports and my HDD says that it supports USB 2.0 and USB 3.0 which appears to be at least half true since I can access it.....sometimes. After speaking with Apple support I came to the conclusion that perhaps this drive isn't as compatible as it could be so I have purchased a Thunderbolt to USB 3.0 adapter to see if that works. That way the HDD will at least be attached to a legitimate USB 3.0 port so there should be no concerns with compatibility. In theory. Has anyone else tried those Thunderbolt adapters?

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USB 3.0 device connecting into USB 2.0 iMac ports