KB2709: Backing up Hyper-V guest cluster based on VHD set
www.veeam.com › kb2709Aug 22, 2018 · To fix this issue, make sure that all shared drives in the cluster that are part of the backup are online. Error Event 19100 Hyper-V-VMMS 19100 'BackupVM' background disk merge failed to complete: General access denied error (0x80070005) This issue occurs because of a permission issue. To fix this issue, the folder that holds the VHDS files and their snapshot files must be modified to give the VMMS process additional permissions.