During the configuration of the Windows Server Backup in server 2012 R2, I get the following error message when formatting my external drive.
'One of the source volumes specified has an invalid format and cannot be protected using Windows Backup. Only volumes formatted with NTFS/ReFS can be protected.'
Seems obvious to me. Reformat the hard drive to match that format. I reformatted under computer management and selected ReFS but I still get the same error message when I run the backup wizard again.