This disk is offline because it has a signature collision with another disk


This is an issue you may see if you are working on more than one cloned operating system at the same time.

You plug in a SD card that you’ve loaded up with a Dexter image, (or any pre-packaged Raspberry Pi image for that matter), using an imaging tool like Etcher, (or dd, or whatever).  You then try to plug in a second  SD card with another image cloned from the same source.

One of the SD cards - usually the second - refuses to mount because “it has a signature collision with another disk. . .”

The original image that was packaged up, and that you write to your SD media, comes with a pre-defined UUID, (unique identifier) for the disk - AND  that “unique” ID is exactly the same  for every  disk created from that specific image.  The reason is that - unlike other disk cloning tools - tools like Etcher and dd do NOT  re-assign a new unique ID to each disk.

(NB: I’m going to post a bug/enhancement request on Balena’s site about this.)

This can be fixed relatively easy on Windows using the “diskpart” utility.  I am sure that there are similar utilities available for Linux and Mac systems.

Rather than re-invent the wheel for anyone running Windows, I’ll just link to an article I found that (ahem!), “reminded me” how to change the UUID on the offending disk.  In fact, all you have to do is pick a number, somewhere in the existing UUID, and change it to something else, then un-mount, unplug, and re-insert the drive.

Piece of cake!

1 Like


On my installation of Windows 10 Pro on a HP Elitebook 85670p, I had to remove both  and swap USB ports for it to actually re-read all the configuration data from the SD cards and resolve the collision.

IMHO, this is a bug in Win-10, (or, more likely, the USB driver), as it should re-read the disk’s config at every re-mount, or at least when re-inserted into the same slot.