The problem is resolved.   - I have deleted all vNICs and their settings and recreated them again. - Assigned VLAN ID. - Reconfigure iSCSI/MPIO - Reconnected to Clarian storage (I did not unassign Server, nor the Virtual Disk) - Back to Windows Disk Management !!!  - The disk was GPT protected. - Moved to CMD with diskpart - CMD diskpart clean successful  The disk is there online. Created partition and formatted the disks.    Thank you for your time. Jimm
Hi,  We have 1 EMC-AX4  Model AX4-5i used as storage with  2 nodes ESX4.1 in a cluster. The storage has 4 iSCSI ports.  We are moving from VMware to Hyper-V (Windows 2012). on the storage, I have recreated 1 virtual disk with  750GB used before  by ESX. The rest of the virtual disks are still assigned to 1 ESX . There is no more clsutter as the second ESX  has Hypervisor 2012 (Hyper-V core).   The registration of the Windows server and the assignemnt of the Virtual disk on EMC-AX4 work fine and the status of connection is OK. The same also on Windows 2012 with iSCSI and MPIO.No error.  My problem: The disk is listed in Windows Disk Management as "Unknown. Not initialized". Trying to initiliazed the disk brings this error: "Virtual Disk Manager.  The device is not ready". When I click OK, the next errro is "Virtual Disk Manager.  The media is write protected". The error are the same with GUI or Diskpart.  Thanks
EMC-AX4 Model: AX4-5i with Windows 2012 iSCSI disk error device is not ready