The disk is offline because it has a signature collision with another drive that is online

diskmanagementI figured out how to resolve the issue in Disk Management in computer management.

So you went to computer management and then to disk management and see your disk listed but there is no drive letter. but there is a disk number and an exclamation point next to it and under the drive number you see “offline”.
you wave your mouse over the exclamation and see this little tip bubble
“the disk is offline because it has a signature collision with another drive that is online”
How do you fix that?
You can try Microsoft’s tip to use cmd and :

In Disk Management, right-click the disk marked Missing or Offline.

Click Reactivate Disk. The disk should be marked Online after the disk is reactivated.

To reactivate a dynamic disk by using a command line

Open a command prompt and type diskpart.

At the DISKPART prompt, type list disk. Make note of the disk number of the missing or offline disk that you want to bring online. Missing disks are numbered M0, M1, M2, and so on, and offline disks are numbered 0, 1, 2, and so on.

At the DISKPART prompt, type select disk .

At the DISKPART prompt, type online.

This did not work for me at all.
What I did find however is if you put your mouse over the disk number (Disk 0,Disk1,Disk 2, etc.) and right click, you have the option to turn the drive to “online”.

and that resolved the issue.
After many failed attampts to search forums fo rthe help, this came as total accident while looking for more text and deeper search terms to help find how to turn the hard drive back online.