Run two external hard drives?

I can only run one at a time instead of two. I would like to copy my 1.5tb over to my 2tb so I have a back up.

My laptop only holds 200GB of remaining data so I can't use that hard drive or I would.

Anyone have a clue on this?

Thanks and really could do with the help.

What seems to be the problem? Not enough USB ports, only 1 drive is recognized in Windows, you get an error when you try to copy from 1 to the other?????

I have enough USB ports using my hub which allows me four extra but just can't run two at a time. First one is perfect but second comes up needed a format. So I format with it being empty but still won't allow me to access them both.

I guess setting or a total wipe through disk management - question is how?

Thanks for your info and more would be very welcome

Are the external drives powered?
If not, the Hub, if not powered, may not be suppling enough power for both drives.

Both drives are mains powered and I thought maybe setting up another win 7 machine which I have already and putting one on each and then using my easy transfer cable?

Need to test the theory but might struggle as I think it will only write to the main c: drive but it will have no problem reading from other machine.

Hmmm I wonder if I can pull that plan off?

Have you tried connecting both to the computer without the Hub?

I'm running both of my externals over a USB hub, and the hub and drives all have their own AC power also. I've never encountered a problem like this...

Do both drives work properly when one or the other is the only one plugged in and on? I'd see about that first, then try plugging them in one at a time both with and without the USB hub. Could even be a problem with a USB data cable so I'd swap them and see what happens when you try using them one-at-a-time after that too (to check if the unrecognized one changes over to that drive with the other drive's cable).

Passing those tests, then perhaps the drives themselves are simply conflicting. Apparently some of them do this, especially if they're different brands or one is new and the other old. A fix for that is potentially (and I say potentially because it's never happened to me and I've never had to do this personally, just know about it)...

Make sure both externals are powered on and plugged in, then:

Start > Search "Computer Management" > open Computer Management. Under "Storage" in left-pane of the Computer Management window (click the tree arrow if its not open already), enter Disk Management.

Now, in the Disk Management window, if you see both of your external drives are in there (recognized by windows), and one of them says "Offline" you will need to right-click on that drive and select "Go Online".

And that SHOULD do it, if this is the issue.

I'm spent for ideas after that, hope someone else can help you if I didn't.


EDIT: Actually, are both externals formatted to NTFS?

Thanks for the info MagusMagnus, your solution was right on the money!