indicium
Contributor
Contributor

Existing VM's EFI

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Can I modify an existing VM's .vmx file from MBR to EFI or does it only work when creating new VM's?

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dariusd
Leadership
Leadership

Hi indicium,

Our virtual EFI implementation does not include a Compatibility Support Module, which is required to boot a non-EFI-aware OS using EFI.

Contrary to lakshya32's advice, if you have an existing VM with an installed OS and you switch it from BIOS to EFI, it will almost certainly be rendered unbootable.  Switching the firmware back to BIOS should restore the VM to operation; Otherwise, as dayworker correctly says, you will need to reinstall the OS so that it is partitioned for EFI (using GPT instead of MBR) and has the EFI bootloader installed instead of the BIOS bootloader.

Let me know if you have any further questions!

Cheers,

--

Darius

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Dayworker
Enthusiast
Enthusiast

You can change this setting but in most cases you have to install the guest from scratch.

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lakshya32
Enthusiast
Enthusiast

Hi

Welcome to communities.

both answer is yes

please let us know if have any problem after edit.

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dariusd
Leadership
Leadership

Hi indicium,

Our virtual EFI implementation does not include a Compatibility Support Module, which is required to boot a non-EFI-aware OS using EFI.

Contrary to lakshya32's advice, if you have an existing VM with an installed OS and you switch it from BIOS to EFI, it will almost certainly be rendered unbootable.  Switching the firmware back to BIOS should restore the VM to operation; Otherwise, as dayworker correctly says, you will need to reinstall the OS so that it is partitioned for EFI (using GPT instead of MBR) and has the EFI bootloader installed instead of the BIOS bootloader.

Let me know if you have any further questions!

Cheers,

--

Darius

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indicium
Contributor
Contributor

I'm going to leave the existing VM's alone and use EFI the next time I create a new VM.

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