Azure Site Recovery failback with VMware EFI Vms ?

New Contributor



I have a question about Azure Site Recovery (ASR) and I could not find an appropriate community and space, but if there is one, feel free to point me to it.


I'm planning to deploy ASR for an on-premises environment with VMware machines running Windows. According to the rollup 42 from November 2019, ASR now supports VMware VMs with UEFI-based boot architecture. This matrix also indicates that UEFI (not Secure UEFI) is supported with Windows. Now if I look at this page, I can read the following:


Boot Type: Boot type of the VM. It can be either BIOS or EFI. Currently Azure Site Recovery supports Windows Server EFI VMs (Windows Server 2012, 2012 R2 and 2016) provided the number of partitions in the boot disk is less than 4 and boot sector size is 512 bytes. To protect EFI VMs, Azure Site Recovery mobility service version must be 9.13 or above. Only failover is supported for EFI VMs. Failback is not supported.


Can someone confirm that ASR does not support failback for EFI VMs and therefore we need to convert BIOS from EFI to Legacy ?


Thanks in advance


2 Replies
best response confirmed by Nicolas Wipfli (New Contributor)



Someone from Microsoft France pointed me to the release notes for the rollup 42 which confirms that failback is supported.


Azure Site Recovery now supports test failover, failover & failback of VMware and Azure machines with UEFI layout


So, this question is answered.




One thing to be aware of is that Secure Boot is not supported for VMware / Physical VMs (as of October '22).  We've just set up a proof of concept and found the agent installation fails with this configuration (as is mentioned in the support matrix).  Secure Boot had been enabled to support enabling 'Device Guard' on Windows 2016+ server OS. 


UEFI with Secure Boot disabled = supported.

UEFI with Secure Boot enabled = not supported.


You can run msinfo32 to get Secure Boot status, or in a script use Confirm-SecureBootUEFI.