I am experiencing this same issue when backing up a 14.04 LTS Gen 1 VM using Veeam. The error seems to occur when the VSS snapshots are being taken. The error did not occur until I had followed Microsoft's instructions on packages to install for Ubuntu (https://technet.microsoft.com/en-GB/library/dn531029.aspx).
I am experiencing this same issue when backing up a 14.04 LTS Gen 1 VM using Veeam. The error seems to occur when the VSS snapshots are being taken. The error did not occur until I had followed Microsoft's instructions on packages to install for Ubuntu (https:/ /technet. microsoft. com/en- GB/library/ dn531029. aspx).