Migrating a Windows VM from Azure to OCI is straightforward if you follow the official supported path using VHD export, conversion to QCOW2, and importing as a custom image. This guide is based on real-world tested steps (as of November 2025) and focuses on a paravirtualized Windows instance launch (recommended for best performance).

Tested on: Windows Server 2016/2019/2022 VMs with data disks up to 1 TB

Goal: Fully working Windows VM in OCI with all original disks preserved

Step 1: Prepare the Target Environment in OCI

1. Create a New Compartment

Go to Identity & Security > Compartments → Create Compartment

Name it something meaningful (e.g., Azure-Migration)

2. Create a VCN and Public Subnet

Networking → Virtual Cloud Networks → Create VCN

  • Add a public subnet (enable "Public" and assign a route table with Internet Gateway)

3. (Optional) Pre-create the final VM shape

You'll launch the real instance later from the imported image. For now, just note your desired shape (e.g., VM.Standard.E4.Flex, 4 OCPU, 64 GB RAM).

4. Create an Object Storage Bucket for Image Import

Storage → Buckets → Create Bucket

Name: image-import-bucket (or any name you prefer)

Step 2: Prepare the Azure Windows VM

1. Download and Install Oracle VirtIO Drivers

Inside the running Azure VM:

  • Download: https://docs.oracle.com/en-us/iaas/Content/Compute/References/windowsvirtiodrivers.htm
  • Run the installer → Reboot

If you want to generalize the image:

C:\Windows\System32\Sysprep\sysprep.exe /oobe /generalize /shutdown

3. Stop the VM in Azure Portal (deallocated state)

4. Create a Full Snapshot of the OS Disk

VM → Disks → OS Disk → Create Snapshot → Choose Full snapshot type

5. Export the Snapshot

Snapshot → Export → Generate URL (valid for 1 hour by default, but you can set longer)

Example URL (do not use this one – generate your own):

text https://md-...blob.storage.azure.net/.../abcd?sv=...&sig=...

Step 3: Download the VHD from Azure

You can do this from any machine (Windows or Linux) with internet access.

Option A – Windows (using AzCopy)

# Download AzCopy Invoke-WebRequest -Uri https://aka.ms/downloadazcopy-v10-windows -OutFile azcopy.zip Expand-Archive azcopy.zip -DestinationPath "C:\azcopy" cd C:\azcopy\azcopy* # Copy VHD to local drive (example: H:\Images) .\azcopy copy "https://your-generated-snapshot-url-here" "H:\Images\VM99.vhd"

Option B – Linux

wget -O azcopy.tar.gz https://aka.ms/downloadazcopy-v10-linux tar -xf azcopy.tar.gz sudo cp azcopy_linux_amd64_*/azcopy /usr/local/bin/ azcopy copy "https://your-generated-snapshot-url-here" "/mnt/data/Images/VM99.vhd"

Step 4: Convert VHD to QCOW2

Install QEMU (if not already present).

Windows

# Using QEMU installed in default location "C:\Program Files\qemu\qemu-img.exe" convert -f vpc -O qcow2 "H:\Images\VM99.vhd" "H:\Images\VM99.qcow2"

Linux

qemu-img convert -f vpc -O qcow2 /mnt/data/Images/VM99.vhd /mnt/data/Converted/VM99.qcow2

Step 5: Upload QCOW2 to OCI Object Storage

Install and configure OCI CLI on your local machine:

https://docs.oracle.com/en-us/iaas/Content/API/Concepts/cliconcepts.htm

# Windows or Linux oci os object put --bucket-name image-import-bucket --file "H:\Images\VM99.qcow2"

Step 6: Import Custom Image in OCI

  1. Go to Compute → Custom Images → Import Image

  2. Choose:
    - Compartment
    - Bucket and Object Name (VM99.qcow2)
    - Image Type: QCOW2
    - Launch Mode: Paravirtualized (best performance)
    - Boot Type: BIOS (recommended for Windows)

Import takes 30–90 minutes depending on size.

Step 7: Fix Boot Mode (UEFI vs BIOS)

By default, OCI may set the image to UEFI. Windows VMs exported from Azure are usually BIOS.

  1. After import completes → Custom Image → Actions → Edit Image Capabilities
  2. Change Guest Boot Mode from UEFI_64 to LEGACY_BIOS
  3. Save

Step 8: Launch the Instance

Compute → Instances → Create Instance

  • Image: Your newly imported custom image
  • Shape: Your desired shape
  • VCN & Subnet: The ones created earlier
  • Add your SSH key or Windows password

First boot behavior:

You may see a black screen for 5–10 minutes or the instance may appear stuck. This is normal for the first boot of imported Windows images.

If it doesn't come up:

  • Reboot the instance once or twice (this often resolves it)
  • Use OCI Serial Console or Simple Console Connection: https://blogs.oracle.com/cloud-infrastructure/post/simple-console-connections-for-windows-administrators

Once Windows boots, install the OCI VirtIO drivers again if needed (usually already present).

Final Notes

  • Data disks: Repeat the snapshot → export → convert → upload → attach as block volume process (or use Azure Disk Export if available).
  • Networking: Assign public IP or set up VNIC as needed.
  • Licensing: Bring your own Windows license or use OCI's licensed images if applicable.

You now have a fully migrated Windows VM running natively in Oracle Cloud Infrastructure with optimal paravirtualized performance!

Happy migrating! 🚀