External Drive Works in One Dock But Not Another

[ces62853]

Hi All,

I've got 2 external drives in a dual bay dock. Both were working fine up until yesterday when I was copying files from my computer to one of the external drives and I got an error (about 80gb in) that it couldn't complete the transfer. It continued to give me error messages every time I tried to reinitiate the transfer, so eventually I decided to unmount and try again. But then it wouldn't eject either of the drives. So I force ejected them. And after that they no longer mounted at all.

Disk 1 continued to be recognized by Disk Utility, which told me it was dead and couldn't be repaired, so I DiskWarriored it and it's fine. It mounts just fine from the dual bay dock.

Disk 2, however, wasn't showing up at all in Disk Utility, so I thought maybe the drive really was gone or something had happened to that bay of the dock. I tried it in the other bay and still nothing. I tried it on its own in the dock and still nothing. So then I put it into another dock that I have and the computer all of a sudden recognized it. I DiskWarriored it too and now it works fine from the second dock. But when I put it back in my dual bay dock, the computer still doesn't recognize it.

One last thing. When both drives are in the dock (and it's showing Disk 1 in the Finder), if I remove Disk 2, it doesn't like that and automatically unmounts Disk 1.

Does anyone know what's going on or have a fix? I normally wouldn't care about having to use multiple docks except that the dual bay dock is convenient because (a) I can connect it to my wireless router and have 2 wireless drives and (b) it's a USB 3.0 connection where my alternate dock is only 2.0.

Any help would be greatly appreciated! Thanks!

 

[Fishrrman]

I, too, have run into problems when connecting external USB docks, drives, and dongles.

Some of them have been like yours -- drives that dismount when another is mounted, or won't mount at all.

I'm going to -guess- that some of these irregularities are due to discrepancies between the USB controller chips used in various docks and dongle adapters (enclosures, too).

It could also be a problem with disk drivers which [I assume] get written to a drive during initialization, and can become corrupted later on.

Back in the old days of SCSI and Apple "HDSC setup" utility, there was an option to "update the drivers" on a connected disk. I'm -guessing- that this command wrote a clean set of disk drivers to the drive.
But there seems to be no such equivalent command in USB. I'm not sure if Disk Utility's "Repair disk" command will update a disk's drivers.
Perhaps (with USB) the only way to put a "fresh and clean" set of drivers onto a disk is to re-initialize it.

I would suggest that you re-initialize "Disk 2" in the dual dock.
Of course, anything on it that you wish to save, you'll have to copy elsewhere first.
No promises that this will work...