Dell Backup & Recovery create Rescue Disk: ERROR: "An Error occurred while creating the rescue disk"

I havethe latest version of Dell Backup & Recovery and have tried several times to create Rescue Disk. 

The software correctly finds my external USB drive but each time I start the process, I receive the following error message:
"An Error occurred while creating the rescue disk"

I have a Dell OptiPlex 7010 01 running Windows 8.1 Professional (x64) (build 9200)

I am trying to backup to external USB hard drive WD 2TB, formatted NTFS (WD Elements 10B8, s/n WX21AA310518, rev 1007).

How to resolve? Can Dell please help?

Thanks, Fred