Specific external hdd cable not being recognized on Mac, but fine on PC

con

macrumors newbie
Original poster
Feb 18, 2012
4
0
A specific USB cable for an external hard drive seems to offer nothing else than to conduct power for the external hdd when plugged into the Mac, as the hdd powers on but no signal appears to be transferred as nothing appears in Disk Utility or third-party recovery apps. Changing USB ports didn't help. But when I switch the cable for another of the same type the hdd is then identified and works.

However, the cable that isn't being picked up on the Mac works perfectly on the PC, making me wonder whether the cable is actually damaged or something in the "settings" associated with that cable is incorrect, if that's even possible.

The hard drives in question are NTFS-formatted and I'm using Paragon NTFS for Mac to access NTFS drives. The issue started occurring not long after the hard drives encountered constant freezing/crashing of the Chrome OS Files app on a Chromebook when trying to browse files on them, and at one point the hard drives kept shutting down within seconds of inactivity while connected to the Chromebook due to an apparent issue with the OS. However, I think on at least one occasion the cord in question still worked on the Mac after said Chrome OS issue, although maybe I misremembered. Anyway I'm not implying Google's poor OS is the cause of the Mac-unreadable-cord. Any advice on what's happening and how to rectify this is appreciated.
 

cmaier

Suspended
Jul 25, 2007
18,029
15,967
California
If the cord is marginal it may well work on a windows machine and not on a Mac. Or even on one windows machine and not on another. They use different usb circuitry and one may be more tolerant of errors than another (eg the Mac may give up after it can’t get a solid signal in 100 microseconds whereas the windows machine may try longer). Or they may have slightly different voltage requirements.

the cable has no digital circuitry in it if it’s just a usb cable, so not much you can do other than use the cable that works.
 

Fishrrman

macrumors Core
Feb 20, 2009
19,390
6,703
Cables are cheap.

Use the cable that works.

Toss the one that doesn't (or use it only with the PC).
 

con

macrumors newbie
Original poster
Feb 18, 2012
4
0
Cable is suddenly working again today. However seems like a close shave:
Current Available (mA): 900
Current Required (mA): 896
 

Fishrrman

macrumors Core
Feb 20, 2009
19,390
6,703
Are the hard drives 2.5" or 3.5" ?
If they are 3.5", do they have their own power supplies?
If so, are you using them?
If the Mac can't supply enough bus power... then the drive... won't mount up...
 
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