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    Server Migration Center:Operating system migration (Windows)

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    Server Migration Center:Operating system migration (Windows)

    Last Updated:Sep 19, 2025

    If your operating system has reached its end of life (EOL) or you need to upgrade it for business purposes, you can use Server Migration Center (SMC) to migrate the OS. This process retains the data on the system disk of your ECS instance. This topic describes how to use SMC to migrate Windows Server 2008 R2, 2012 R2, 2016, or 2019 to a later version.

    Background information

    Microsoft ended support for Windows Server 2008/2008 R2 on January 14, 2020, and for Windows Server 2012/2012 R2 on October 10, 2023. If you have ECS instances that use these operating systems, we recommend that you take action to continue receiving software updates and security patches. This helps prevent issues caused by the EOL of the operating systems. For more information, see Windows Server operating systems. The operating system migration feature of SMC provides several migration paths. After the migration, the OS kernel version and major system packages are upgraded, and the data on the system disk is retained.

    Note

    If you do not need to retain system disk data or if you need more OS conversion options, you can change the operating system by replacing the system disk.

    Migration paths

    Windows Server 2008 R2

    Support for Windows Server 2008 R2 has ended. You can migrate it to Windows Server 2016 or 2019, which are in the mainstream support phase, to ensure your applications run in a supported environment.

    Important

    Due to limitations of the Windows OS migration feature, you cannot directly migrate Windows Server 2008 R2 to Windows Server 2016 or 2019. You must first migrate to the intermediate version, Windows Server 2012 R2.

    1. Migrate Windows Server 2008 R2 to the intermediate version, Windows Server 2012 R2.

      System architecture

      Source operating system

      Target operating system

      X86

      Windows Server 2008 R2 Standard Edition 64-bit Chinese/English

      Windows Server 2012 R2 Datacenter Edition 64-bit Chinese/English

      Windows Server 2008 R2 Enterprise Edition 64-bit Chinese/English

    2. Migrate Windows Server 2012 R2 to Windows Server 2016 or 2019.

      System architecture

      Source operating system

      Target operating system

      X86

      Windows Server 2012 R2 Datacenter Edition 64-bit Chinese/English

      • Windows Server 2016 Datacenter Edition 64-bit Chinese/English

      • Windows Server 2019 Datacenter Edition 64-bit Chinese/English

    Windows Server 2012 R2

    Support for Windows Server 2012 R2 has ended. You can migrate it to Windows Server 2016 or 2019, which are in the mainstream support phase, to ensure your applications run in a supported environment.

    System architecture

    Source operating system

    Target operating system

    X86

    Windows Server 2012 R2 Standard Edition 64-bit Chinese/English

    • Windows Server 2016 Datacenter Edition 64-bit Chinese/English

    • Windows Server 2019 Datacenter Edition 64-bit Chinese/English

    Windows Server 2012 R2 Datacenter Edition 64-bit Chinese/English

    Windows Server 2016

    System architecture

    Source operating system

    Target operating system

    X86

    Windows Server 2016 Standard Edition 64-bit Chinese/English

    • Windows Server 2019 Datacenter Edition 64-bit Chinese/English

    • Windows Server 2022 Datacenter Edition 64-bit Chinese/English

    Windows Server 2016 Datacenter Edition 64-bit Chinese/English

    Windows Server 2019

    System architecture

    Source operating system

    Target operating system

    X86

    Windows Server 2019 Datacenter Edition 64-bit Chinese/English

    Windows Server 2022 Datacenter Edition 64-bit Chinese/English

    Migration restrictions

    • Cross-language migration for Windows is not supported.

    • Only specific migration paths are supported.

    • The Windows instance that you want to migrate must have an instance type of 2 vCPU and 2 GiB or higher.

    • The OS migration tool downloads and installs software packages during the migration. Before you migrate, ensure that the C drive of the instance has at least 20 GiB of free space and that the free space is larger than the size of the C:\Windows folder.

    • You cannot migrate an instance while a snapshot is being created for it. Wait for the snapshot creation to complete before you start the migration.

    • Windows OS migration is supported only in the following regions.

      Asia Pacific - China

      Asia Pacific - Other

      Europe & Americas

      Middle East

      • China (Hangzhou)

      • China (Shanghai)

      • China (Qingdao)

      • China (Beijing)

      • China (Zhangjiakou)

      • China (Hohhot)

      • China (Ulanqab)

      • China (Shenzhen)

      • China (Heyuan)

      • China (Guangzhou)

      • China (Chengdu)

      • China (Hong Kong)

      • China (Wuhan - Local Region)

      • Japan (Tokyo)

      • South Korea (Seoul)

      • Singapore

      • Malaysia (Kuala Lumpur)

      • Indonesia (Jakarta)

      • Philippines (Manila)

      • Thailand (Bangkok)

      • Germany (Frankfurt)

      • UK (London)

      • US (Silicon Valley)

      • US (Virginia)

      SAU (Riyadh - Partner Region)

    Precautions

    Important

    Before you migrate the operating system, make sure you understand the following precautions.

    Migration phase

    Precautions

    Before migration

    • Complete the pre-migration preparations. For more information, see Preparations.

    • Before you start the migration, understand the migration restrictions. Fully test and verify all your applications in the target OS environment beforehand. This ensures compatibility and performance between your applications and the target OS and helps prevent operational issues or functional failures after the migration.

    • During the migration, the system kernel and software packages of the source instance are installed or updated. The instance restarts multiple times automatically. Your applications will be unavailable during this period. Before you start, assess the impact and pause your services.

    During migration

    • During the migration, do not stop, restart, or release the ECS instance manually or using O&M scripts. Otherwise, the migration may fail.

    • A migration drill or cancellation might trigger an automatic rollback to the pre-migration snapshot. Data generated during the migration will be lost.

    • The migration process involves several operations on the ECS instance. These include creating snapshots, converting the OS kernel version, reinstalling and upgrading software packages, and stopping and starting the instance. Back up important data in advance and schedule a suitable migration window to avoid business interruptions.

    • During a Windows migration, a snapshot of the Windows installation media is automatically shared with your Alibaba Cloud account. This snapshot is used to create an intermediate disk that is attached to the instance. Do not perform any operations on this disk during the migration. The intermediate disk is automatically detached and released after the migration is complete.

    • During the migration, the system checks the migration conditions and performs a pre-migration assessment on the source instance. If the source system does not meet the conditions or the pre-assessment fails, the migration stops with an error. Success is not guaranteed. Familiarize yourself with the migration conditions and troubleshooting documents, and run tests in advance. For migration issues, see Troubleshoot Windows OS migration issues.

    After migration

    • After the migration, the instance starts automatically. The instance ID, image ID, VPC, public and private IP addresses, and hostname remain unchanged. The operating system is changed to the target OS.

    • The data on the original system disk is retained. However, your applications might not run correctly due to changes in the environment or dependencies. This can cause service interruptions. Make sure to test and verify your applications.

    Migration operations

    Important

    During the migration, SMC creates pay-as-you-go snapshots of all disks attached to the ECS instance to back up data. You will be charged for these snapshots. For more information, see Billing.

    Quick migration (recommended)

    Note

    If your instance was purchased before December 1, 2017, was created from a custom image that you uploaded, or is a third-party server, you must install Cloud Assistant Agent on the ECS instance to use this method. ECS instances created from public images after December 1, 2017 have the Cloud Assistant Agent pre-installed by default. This note does not apply to such instances.

    1. Log on to the Server Migration Center (SMC) console.

    2. On the OS Migration page, click Start Migration.

    3. In the Migrate Operating System dialog box, select the ECS instance to be migrated and click Pre-check.

      You can filter ECS instances by instance ID and region.image

    4. In the Migrate Operating System dialog box, the system automatically conduct pre-migration checks for the operating system, which will take approximately 10 seconds.

      • When the pre-check status changes from image to image, it indicates that the pre-check has passed.

      • When the pre-check status changes from image to image, it indicates that the pre-check has failed. You can follow the prompts to fix the issues and attempt the migration again.

    5. After carefully reading the usage notes for operating system migration, select I acknowledge and accept these risks and authorize Alibaba Cloud to create snapshots for all disks on the instance and click Next.

      image

    6. In the pop-up Migrate Operating System dialog box, select the destination operating system as needed.

      • Select the Same Destination Operating System: If you migrate the operating systems of multiple ECS instances at a time, you can select this option and specify a destination operating system for all the selected instances.

      • Select Destination Operating System by Instance: If you migrate the operating systems of multiple ECS instances at a time, you can select this option and specify a destination operating system for each selected instance.

    7. Click Check for Migratability and view the check results.

      The migratability check requires approximately 30 seconds to complete.

      • image: You can migrate the instance to the destination operating system.

      • image: You cannot migrate the instance to the destination operating system. You can follow the on-screen instructions to view the reason why you cannot migrate the instance to the destination operating system.

    8. Click Migrate.

      You can view the operating system migration progress on the Migrate Operating System page.

      Warning

      During the migration process, do not stop, restart, or release the ECS instance in manual mode or by using O&M scripts. Otherwise, operating system migration fails.

      image

    Step-by-step migration

    Step 1: Import the migration source

    Migration sources can be servers of a variety of types to migrate, such as servers in data centers, VMs, and hosts on third-party cloud platforms. SMC supports multiple methods to import the information about migration sources. You can select a method based on your business requirements. For more information, see the How do I choose a method to import migration sources? section of the "FAQ" topic.

    Import the migration source using a command (recommended)

    Important

    • The source server must be accessible over the Internet. If your source server is protected by a firewall, refer to What are the service domains of SMC? and ensure that the corresponding domains and ports are whitelisted in your network security policy.

    • If your source server cannot access the Internet or you want to improve migration efficiency through the VPC, use the method of importing by client.

    1. Go to the SMC console - OS Migration page.

    2. On the OS Migration page, click Import Migration source.

    3. Configure the parameters as prompted and copy the activation code command. The following table describes the parameters.

      Parameter

      Description

      Migration Source Type

      Alibaba Cloud ECS Instance.

      Import Method

      Select Use CLI to Import Server. Generate an activation code and a command, and run the command on the migration source.

      Activation Quota

      The number of migration sources whose information you want to import by using the activation code. Valid values: 1 to 1000. Default value: 200.

      Validity Period

      The validity period of the activation code. Unit: day. Valid values: 1 to 90. Default value: 90.

      Activation Code

      The activation code. Perform the following steps to generate the activation code and copy the generated command:

      1. Click Generate.

      2. Click the Windows Powershell tab.

      3. Click Copy to copy the activation code command.

    4. Import the migration source.

      1. Log on to the Windows server.

      2. Open Windows PowerShell as an administrator.

      3. Run the copied command to import the information about the migration source.

        image.png

        After the command is run, if a message similar to Import Source Server [s-bp19rlidl3mwuptc****] Successfully! is returned, the information about the migration source is imported.

        If the command fails to run, see What do I do if the command fails to be run when I import the information of a Windows migration source by using the CLI?

    5. On the OS Migration page in the SMC console, check the status of the migration source in the Real-time Migration Status column.

      • If the status of the migration source is Migration SourceOnline, the information about the migration source is imported.

      • If the migration source is in another state, the information fails to be imported. In this case, troubleshoot the failure based on the following solutions and import the information about the migration source again:

        • Troubleshoot the issue based on the message displayed in the SMC console or the log file in the directory where the SMC client is installed. By default, the SMC client is installed in the C:\smc directory.

        • For more information about frequently asked questions (FAQ) and solutions, see FAQ and Errors occurred during a server migration.

    Import the migration source using the SMC client

    For more information about the SMC client, see SMC client guide.

    1. Go to the SMC console - OS Migration page.

    2. On the OS Migration page, click Import Migration source.

    3. On the Import Migration Source page, configure the parameters. The following table describes each parameter.

      Parameter

      Description

      Migration Source Type

      Alibaba Cloud ECS Instance

      Import Method

      Select Client Import.

      Import Instructions

      In the Import Instructions section, download the appropriate SMC client for your source server's operating system (Linux or Windows) and architecture (32-bit or 64-bit).

    4. Import the information about the migration source.

      Important

      During the migration, do not shut down the SMC client until the migration is complete. Otherwise, the migration source is disconnected from the SMC console, and the migration fails.

      1. You can use a remote connection tool that supports file transfer. For example, you can use WinSCP to upload the SMC client package to the source Windows server.

      2. On the source Windows server, use the built-in decompression tool of Windows or the decompression tool that you install to decompress the SMC client package.

      3. In the SMC client folder that corresponds to the source server, run the SMC client.

        • To run the Windows GUI version, double-click the go2aliyun_gui.exe file.

        • To run the Windows CLI version, double-click the go2aliyun_client.exe file.

        Note

        When you run the program, you must click OK to confirm that you have the administrator permissions.

      4. Obtain an activation code or AccessKey pair.

        • (Recommend) Obtain an activation code: In the Description section in the SMC console, click Generate and copy the generated activation code information.

        • Obtain an AccessKey pair: An AccessKey pair consists of an AccessKey ID and an AccessKey secret. If no AccessKey pair is created, create one first. For more information, see Obtain an AccessKey pair.

      5. Enter the activation code or AccessKey pair as prompted.

        • To run the Windows GUI version, enter the activation code or AccessKey pair in the Token Id/AK and Token Code/SK fields and click Start. For more information, see Use the SMC client.

        • To run the Windows CLI version, enter the obtained access_access_token_id and access_token_code and press the Enter key.

        If the information about the migration source is imported, a message similar to the following one is returned: Import Source Server [s-bp18x8751kgz2oyh****] Successfully!

    5. On the OS Migration page of the SMC console, you can check the status of the migration source in the Real-time Migration Status column.

      • If the status of the migration source is Migration SourceOnline, the information about the migration source is imported.

      • If the migration source is in another state, the information fails to be imported. In this case, troubleshoot the failure based on the following solutions and import the information about the migration source again:

        • Troubleshoot the issue based on the message displayed in the SMC console or the log file in the directory where the SMC client is installed. By default, the SMC client is installed in the C:\smc directory.

        • For more information about frequently asked questions (FAQ) and solutions, see FAQ and Errors occurred during a server migration.

    Step 2: Configure the migration

    1. Find the migration source that you want to manage and click Start Migration in the Actions column.

    2. In the Migration Configuration dialog box, configure the parameters.

      The following table describes the OS migration parameters.

      • Current Operating System: The current operating system. This is a read-only field. Example: Windows Server 2008 R2 64-bit Chinese.

      • Target Operating System: Select an operating system from the drop-down list, such as Windows Server 2012 R2 Datacenter Edition 64-bit Chinese.

    3. Click Start Migration. In the Confirm OS Migration dialog box, carefully read the precautions and click I Confirm That I Understand.

    4. On the OS Migration page, you can view the real-time migration status.

      Warning

      During the OS migration, do not stop, restart, or release the Windows instance manually or using O&M scripts. Otherwise, the OS migration will fail.

    Verify the migration result

    • The OS migration is successful if the real-time migration status is Completed.

      image

      Note

      After the migration task is complete, the ECS instance restarts automatically. During the system initialization phase, operations such as updating software packages are performed. Avoid performing any operations on the ECS instance. Wait for the system to start successfully. The initialization phase takes 15 to 30 minutes. The exact duration depends on the number of system software packages.

      In the Operation column of the target migration source, click View Destination Instance. On the ECS instance details page, verify that the operating system has been migrated to the target OS.

      Important

      After the migration is complete, the operating system kernel and software packages of the source operating system are upgraded. Original application data is retained. However, your applications may not run as expected due to changes in the environment or dependencies. In this case, business cannot run as expected. Therefore, you must test and verify a migration solution before you perform a migration job.

    • If the Real-time Migration Status is Error, the migration task has encountered an error.

      In this case, you need to perform the following operations:

      1. Click Troubleshoot Errors in the Actions column and fix issues based on the error code and description. For more information, see FAQ and Errors occurred during a server migration.

      2. After the issues are fixed, click Retry Migration in the Actions column of the migration job.

        The migration job resumes from the point where it was suspended.

        Important

        If the intermediate instance is released, you must create another migration job. For more information, see the What do I do if I accidentally release an intermediate instance? section of the "FAQ" topic.

      To roll back the data on the source system disk, you can use the automatically created backup snapshot for data restoration. Follow these steps:

      1. Go to the ECS console - Snapshots page.

      2. In the Operation column for the automatic backup snapshot, click Roll Back Disk.

      3. In the Roll Back Disk dialog box, click OK.

    Clean up resources

    During the migration, SMC creates pay-as-you-go snapshots named SMC_Backup_Snapshot_XXX for the disks of the ECS instance. If you no longer need these snapshots, delete them to avoid incurring further charges. For more information, see Delete a snapshot.