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Problem: Windows Reactivation Needed After Live Failover

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Root Cause

A VM's re-location from one ESXi host to another (either by VMware Clone, vMotion, or by a BC/DR solution like Zerto Virtual Replication) can cause the Microsoft Windows license mechanism to require a re-activation of the VM's Windows OS. 
This behavior is, unfortunately, an expected one, as the following Microsoft Licensing Briefs explains some of these scenarios depending on the licensing model you may be using.

Microsoft Licensing Briefs: Virtualization

After the re-location of a VM from one physical host to another, the Microsoft Licensing mechanism sees that the server hardware has changed and requires the Windows license to be re-activated. Please note that is a general issue and not specifically limited to Zerto. While Zerto is hardware agnostic, the Windows operating system is not hardware-agnostic by design.


After a Live Failover, some Windows servers may be required for Microsoft Windows license re-activation. 


It is possible to create a script to automate the license activation upon recovery if needed. For more information on running scripts before or after recovery of a VM, please review the section "Running Scripts Before or After Recovering a VPG" within the "Zerto Administration Guide" provided below. 

Zerto Administration Guide

If additional clarification is needed on why specific VMs are required for license re-activation, please kindly consider contacting Microsoft support for a thorough discussion.