TechNet Wiki
https://social.technet.microsoft.com/wiki/contents/articles/1977.hyper...25.11.2010 · If you cannot free up disk space, the merge can not take place even if the VM was turned off. Many we maintain a (250 GB or so) LUN on each Hyper-V cluster that is used for staging and emergencies. You can use System Center Virtual Machine Manager (SCVMM) to migrate the (power off) VM over the network to this "holding" or "temporary" LUN and allow the …