proxmox 4.2 disks migration read only file system

I migrated to 4.2 but when trying to get my old VMs working in the new environement no way !! here's an example I 've : vm1-disk.vmdk (is a vmdk disk in an old proxmox 3 server) that I want to get it work in proxmox 4.2 in a VM with id 100. I tried : 1- to copy vm1-disk.vmdk to...