Windows 7: Two Seagate External Drives, one not recognised

I recently bought a second (and larger) Seagate external drive. Unfortunately, having set the new one up, the first is no longer recognised by my system. It is still fine, as it is recognised by my laptop.

Someone has suggested to me that the driver for the newer drive is, in some way, stopping the older one from being recognised.



Has anyone got any suggestions on how I can use both drives?

Check the two drives in the Disk Management. Right click Computer > Manage > Disk Management.

If a drive letter is not assigned to one drive, assign a drive letter.

jumanji - thank you for your quick response. I have done what you said, and althought I can see the missing drive, there is an error message associated with it that says that the disk is offline because:

The disk is offline because there is a signature collision with another disk that is online.

Ther is obviously a clash of some sort. Any further thoughts?

I pushed the Online link on the screen, and the drive becane visible. Obviously doing that resolved any clash.

jumanji - thank you

Yep, I was about to suggest it and you did it even before I could put it. Good going. Have a happy day. Please mark the thread as solved unless you have any further queries.

EDIT: If you get into the same problem again with these two external drives, then you may have to change the Unique ID of one of the drives.

This article should help you decide whether these have the same uniqueid still and change one if needed. http://www.laurentkempe.com/post/Win...collision.aspx That should nail the problem once for all.

jumanji - thanks again.

I used the uniqueid approach outlined in the link, and interestingly the ids of the two disks in question were 33B27DF5 and 00000000. The second one looks suspicious to me, and I wonder if using the Online mechanism from within Disk Management re-set it to a default number (00000000)?

I will leave it as it is, unless you think I should change it to something more sensible

Yes, that is what it could have done. As long as they are different , you need not bother.

In fact most who did it did not report any further problems necessitating any further change in the unique id.

This problem will arise again only when you have say two other identical drives with the same unique id and you bring one online as you did. That will reset one to 00000000 and then you will have two drives with the unique id 00000000. So again one of the two with the same unique id 00000000 will not show.

But now you know what to do. Check and change the unique id. It can be any 8 digit hexadecimal. The only thing is that it has to be different so that a signature clash does not occur.

It is with this in mind and also to help others who encounter the same problem, I put out the addiional reference as to how to check and change the unique id.

(If you are still worried change 00000000 to 33B27DF4. )