sparse bundle not recognized after migrating to new iMac

I had a 2006 iMac with DAS Drobo. I was sharing the Drobo on the network so another iMac (2010) could also use it for Time Machine. I recently upgraded the 2006 iMac to a 2013 iMac (OS X Yosemite). The DAS Drobo migrated the time machine data from the original 2006 iMac flawlessly. However, the 2010 iMac that was using the Drobo for Time Machine across the network can’t access its Time Machine data anymore. I get a “not recognized” error on the sparse bundle. I can access other data on the shared DAS Drobo, but I can’t access the sparse bundle, either from the 2010 iMac (which “owns” that Time Machine sparse bundle) or from the new 2013 iMac to which the DAS Drobo is directly connected. From both iMacs, I see a red circle with white band across it in the lower right of the sparse bundle icon.

In short, how do I make the sparse bundle recognizable so I can continue with Time Machine on the 2010 iMac?

I can’t exactly say I have the same problem but I am on this forum looking for guidance as to how I attach my existing (early) Drobo to a new iMac. I am aware that somewhere in the works there is a ‘sparse bundle’ that plays a critical role in how a Drobo works with a Mac but where it is and how I ensure it and another critical files, are transferred and then made to work on the new iMac I have no idea.
I’m sure there must be guidance on this site somewhere but I have been unable to find it.

Please advise.

There is a unique identifier embedded in the sparsebundle so Time Machine knows it belongs to a specific machine.

You can edit it to match your new machine.,08,27,169,fix-time-machine-sparsebundle-nas-based-backup-errors.html