1840: VMware ESX Server Guest System Does Not Boot after Restore from Acronis Bootable Media

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Last update: 30-11-2010

ESX Server mounts the storage using UUID. With the hard disk changed, UUID changes too. Hence, ESX fails to mount


  1. You boot an ESX host machine from Acronis Bootable Media;
  2. You back up the machine's hard disk;
  3. After that you replace the hard disk in the machine with an identical one;
  4. You restore the backup to the new disk;
  5. You boot the ESX host machine from the restored disk;
  6. Guest Operating Systems fail to boot and ESX Server cannot recognize the restored disk.


ESX Server mounts the storage using Universally Unique Identifier (UUID). With the hard disk changed, UUID changes too. As a result ESX Server fails to recognize the restored hard disk and mount the storage. Hence, Guest Operating Systems fail to boot.


To migrate ESX Server to new hard disks you need to do the following:

  1. Restore an existing image of ESX Server to new hard disks;
  2. Boot ESX Server and hit Alt-F1 to enter the command-line interface. Log in under root;
  3. Issue the following command:

    esxcfg-advcfg -g /LVM/EnableResignature

    There will be either 1 or 0 value output. If the value is 0, then ESX will not automatically update the VMFS header with new LUN and UUID. Therefore this value should be set to 1:

    esxcfg-advcfg -s 1 /LVM/EnableResignature

  4. Reboot the ESX Server:

    shutdown -r 0

  5. After the reboot you should connect to the ESX Server from the Console and check if the data storage has been mounted properly.

(!) The Guest Operating Systems will remain in the unknown state. So, you should reinitialize guest virtual machines:

  1. In the left menu of ESX Server Console right-click on the guest machine name and click Remove from inventory;
  2. Choose host ESX server-> Configuration;
  3. Under the Hardware section choose Storage and right-click on it (it should contain a list of virtual machines;
  4. Click Browse Datastore;
  5. Choose the .vmx of the machine that was removed from inventory;
  6. Click on the Add this virtual machine to inventory option.

After this the ESX Server should work properly and Guest Operating Systems should boot.

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