disk offline due to signature collision

I cloned my existing hd to a larger size in case the first drive failed. Both drives work when installed alone. When either is used as a secondary external , attachment by usb, the ext is not recognized and gives the signature conflict in disk management. disk part shows they have identical signatures and if I change the id or right click to change offline to online, the disk will be read as a secondary drive. But, the new sig makes it unbootable as a primary drive, defeating the purpose of creating the clone. My question is, if the sig has been changed so that the drive is not bootable, and I no longer have the first drive to see what the sig should be, is there a program that will find and correct the sig to make the drive bootable again? Is it possible to do a system repair or boot repair from a win 7 disk to fix this?

First up giwatcher great idea to clone - something I always do with my machines especially if you want to play with another OS - for example upgrade to 10 - use the clone - if it fails then the original goes back in.

Now I am also guessing here that this might be depending on the drive you are setting as the first boot option in the BIOS and even so I would be real wary of using the clone as an external hooked up afterwards in any case - in case it corrupts the system entirely. Myself and I could be totally wrong that because the clone has a bootable property and I am wondering why you need to have two bootable drives in at the same time.

Would it not be an idea to just get a new external to use?

When you install a disk Windows edited a signature to the drive do it knows what it is as you cloned you need to use disk part go change one signature

Thanks for the reply. Not trying to use 2 bootables on the same machine, but thought I could use the clone as backup storage or to transfer files, only to find out that I can't unless I change the signature of the drive, and then it is no longer bootable. Many google threads recommend right click<select online, which works, but makes the drive no longer bootable. I am trying to find out if the newly non-bootable drive with a changed signature can be repaired if I don't know the original sig for whatever reason.

How did you change signatures with disk part?

I did not change the signatures yet. I realized if I did so that the disk won't be bootable. Again, I am only fact finding and asking that , if I did change the signatures, like many people have by right click>online in disk mgt, and did not know the correct signature to change it back, will a disk repair or other software repair this issue?

The signature is just that a signature so it know what the drive is nothing to do with booting or diskmanagement

How to Change the Disk Signature of a Drive Without Losing Existing Data or Reformatting (howtohaven.com)

giwatcher said:

I did not change the signatures yet. I realized if I did so that the disk won't be bootable. Again, I am only fact finding and asking that , if I did change the signatures, like many people have by right click>online in disk mgt, and did not know the correct signature to change it back, will a disk repair or other software repair this issue?

Click to expand...

I really do not know why you are saying that you can't find the unique ids of both the disks you have and that have the same unique id.

Look at the last screenshot in my post #57. http://www.sevenforums.com/hardware-devices/317436-how-recover-ntfs-partition-6.html#post2652503

There disk 1 and disk 2 have the same unique id.

Can you not note it down and keep it? ( Or better take a screenshot as shown and keep it on a third drive )

In your case assuming that your bootdisk (say Disk 0) and the other one which you are connecting as external (say Disk 1) will have the same unique id. Note it down or screenshot.( actually not necessary)

You will now be changing the unique id of Disk 1 , to avoid the signature collision.( Use disk part command only to change it. The last line in the screenshot shows how to change the Unique Id of the selected Disk.Just change one letter ( A to F)/number( 0 to 9) in any one field as shown in my screenshot.)

If you now want to make it the boot drive, just change the unique ID back to the original unique ID which in any case you will seeing as the unique ID of your boot Disk 0.

Thank you jumanji and samuria for your replies. You both have misunderstood my question. I know the disk1 clone will not boot if I change its signature and don't know to use disk part write down the original signature before I change it. This has happened to those with the disk offline message in disk management who were instructed to right click>online to get access to disk1. They were not told to use disk part to write down the sig, so if they then tried to use disk1 as a bootable disk0, they would no longer have a bootable disk.
My disk1 is a clone of disk0 with the same sig id. If I mounted disk1 and made it online as a secondary disk, and I know nothing of signatures, and if then disk0 has a major malfunction and self destructs, I might say, no problem, I have the clone to use as a bootable disk, as if nothing ever happened. But, guess what- it won't boot because I unknowingly changed its sig.
In that situation, is all hope lost fixing the clone to boot, or can the sig be repaired by loading the win7 repair disk, or by some software that is out there that fixes disk signatures?
Hopefully, I have stated my question clearly this time.

Yours is a hyphothetical question. Why? If you had a signature collision you would change the unique ID of only one drive. Why should you change the unique ids of both the drives?

Anyway to answer your hyphothetical question:

If I don't know what the original unique ID of the two drives that had a signature collision and I had changed the unique ids of both those drives to some random unique ids ( I should be a maverick to do that), then as far as I know there is no way you can get the original Unique id. I would be learning something new if one finds that unique id .

As stated it's nothing to do with booting signatures have no effect on that you can change it to anything its only so windows knows what the drive is booting is done via bios not windows. You keep mentioning disk manager you can't change it in there. If you blank the signature windows will just write a new one like it does for a new disk

Let me restate my example.
I clone an original hd1 and call it hd2. I put hd2 in a drawer for safe keeping, and a month later, after adding files to hd1on my laptop, I decide to put those files onto hd2 to make it up to date. I place hd2 in a usb enclosure and connect. Because they are clones with identical sigs, hd2 is not recognized. I research the problem and am advised to go to dsk mgmt rightclick>online and it works, the hd2 is now recognized and I transfer the files from hd1 to hd2, not knowing that I have changed the sig on hd2 and it will no longer boot as a clone if I need it to. I put this hd2 in a drawer for safe keeping and a month later there is a catastrophic failure of hd1, it won't work at all in any way. No problem, I have a clone to protect from just such an occurrence. Unfortunately, I unknowingly changed the sig of clone hd2 so it won't boot now. Hd1 is unusable so I can't find its sig so as to copy it to hd2.
Will win7 repair fix this? Is there a 3rd party software that is designed to recover a disk sig, eg, BCD or other? This is hypothetical for me, only because in real life I resisted making hd2 online until I researched it. Many people have done this and if they try to boot their clone, they are in for a surprise if the don't have the original hd to find its sig. That is why I am questioning to see if there is a fix.

giwatcher said:

I clone an original hd1 and call it hd2. I put hd2 in a drawer for safe keeping, and a month later, after adding files to hd1on my laptop, I decide to put those files onto hd2 to make it up to date. I place hd2 in a usb enclosure and connect. Because they are clones with identical sigs, hd2 is not recognized. I research the problem and am advised to go to dsk mgmt rightclick>online and it works, the hd2 is now recognized and I transfer the files from hd1 to hd2, not knowing that I have changed the sig on hd2 and it will no longer boot as a clone if I need it to.

Click to expand...

I would never manually modify a clone or backup image to try and get it "up to date".
I would create a new clone or backup image, as needed, to keep it up to date.

If you want to save the signatures before making changes this should work:
Open an elevated command prompt and run these commands to get disk sigs before making changes:

• diskpart
• list disk
• select disk 0
• uniqueid disk
• select disk 1
• uniqueid disk

select each disk and get the uniqueid for each disk sig you want to keep.
You can copy the sig from the CMD window, or save a screen print.

giwatcher said:

Thanks for the reply. Not trying to use 2 bootables on the same machine, but thought I could use the clone as backup storage or to transfer files, only to find out that I can't unless I change the signature of the drive, and then it is no longer bootable. Many google threads recommend right click<select online, which works, but makes the drive no longer bootable. I am trying to find out if the newly non-bootable drive with a changed signature can be repaired if I don't know the original sig for whatever reason.

Click to expand...

Well easy mate if you only want that external to store stuff then maybe you should make the bootable partitions separate on the cloned drive and partition the drive as much as you like say with this https://www.partitionwizard.com/free-partition-manager.html such a really handy tool for doing anything with a drive. For example you could try making the clone partition small and make up others for storage but I am still thinking that having it plugged in when you power on is going to cause issues at some stage of the game.
For my money I would buy another large external drive for storage and use the clone to boot with. The original drive is always there as a safety net.

Many replies, but only alternate suggestions without specifically addressing my question. I'm not sure why no one gets the crux of my question, but I guess I will give up. Thanks anyway.

Well as we have said why this needs to be done in this fashion is a bit of a conundrum because speaking for myself I cannot see any advantage in doing what you want to do because I do understand what you are saying and to me it seems to be making a convoluted method of making sure you have data backed up all the time.

I will again say use the clone to as the everyday drive and keep the original for the back up and I have to say the chances of the clone crashing would be fairly slim unless you did something reckless with it. Make images by all means but you are just making a lot of work for yourself doing it the way you are.

ok, one last time. Of course, everything you said is true. I am not asking permission to do it the way I stated, I am asking if someone has inadvertently changed the signature because they were told to make disk on line in dsk mgt, and didn't know they were changing the sig, and also didn't have the original disk to copy the sig to the clone, is there a repair by win7 disk or 3rd party software to recover the sig and make the dosk bootable again. There are a lot of people being told in forums that offline>online is a quick and risk free solution. It is NOT, unless the sig can be recovered after the fact. I don't know how to state my concern any clearer than that!

giwatcher said:

I cloned my existing hd to a larger size in case the first drive failed. Both drives work when installed alone. When either is used as a secondary external , attachment by usb, the ext is not recognized and gives the signature conflict in disk management. disk part shows they have identical signatures and if I change the id or right click to change offline to online, the disk will be read as a secondary drive. But, the new sig makes it unbootable as a primary drive, defeating the purpose of creating the clone. My question is, if the sig has been changed so that the drive is not bootable, and I no longer have the first drive to see what the sig should be, is there a program that will find and correct the sig to make the drive bootable again? Is it possible to do a system repair or boot repair from a win 7 disk to fix this?

Click to expand...

See this link

https://blogs.technet.microsoft.com/markrussinovich/2011/11/06/fixing-disk-signature-collisions/

Thank you, pbcopter. This is what I was looking for. After looking thru the article, it is just convoluted enough that I may not be able to do it successfully if needed. Have you read it and, if so, do you understand it enough to use it? Do you think a win7 install disk repair option would work?

You're welcome. I have read it and believe I could use it if needed but I have not actually done it yet. I believe if an easier way were possible Mark would not have written the blog the way he did. Just my opinion though.