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Changes in Windows Server AMIs by OS version - AWS Windows AMIs

Changes in Windows Server AMIs by OS version

AWS provides AMIs for Windows Server 2016 and later. These AMIs include the following high-level changes between AWS Windows AMIs for different Windows operating system versions:

  • Windows Server 2025 AMIs use UEFI boot mode by default, except for Windows Server 2025 AMIs named BIOS-Windows_Server-2025-English-Full-Base.

    Note

    EC2 metal instance sizes and some EC2 instance types do not support UEFI boot mode for Windows Server. To launch Windows Server 2025 on these instances, you must use the AWS managed BIOS-Windows_Server-2025-English-Full-Base AMI, or an AMI that is based on that image. For more information about UEFI requirements, Requirements for UEFI boot mode in the Amazon EC2 User Guide.

  • Windows Server 2025 AMIs support Nitro EC2 instance types only.

  • Windows Server 2025 AMIs use gp3 EBS volume types by default.

  • Windows Credential Guard is not supported on AWS Windows Server 2025 AMIs.

Windows Server 2025

  • Windows Server 2025 AMIs use UEFI boot mode by default, except for Windows Server 2025 AMIs named BIOS-Windows_Server-2025-English-Full-Base.

    Note

    EC2 metal instance sizes and some EC2 instance types do not support UEFI boot mode for Windows Server. To launch Windows Server 2025 on these instances, you must use the AWS managed BIOS-Windows_Server-2025-English-Full-Base AMI, or an AMI that is based on that image. For more information about UEFI requirements, Requirements for UEFI boot mode in the Amazon EC2 User Guide.

  • Windows Server 2025 AMIs support Nitro EC2 instance types only.

  • Windows Server 2025 AMIs use gp3 EBS volume types by default.

  • Windows Credential Guard is not supported on AWS Windows Server 2025 AMIs.

Other differences

Note the following additional important differences for instances created from Windows Server 2016 and later AMIs.

  • By default, EC2Launch does not initialize secondary EBS volumes. You can configure EC2Launch to initialize disks automatically by either scheduling the script to run or by calling EC2Launch in user data. For the procedure to initialize disks using EC2Launch, see "Initialize Drives and Drive Letter Mappings" in Configure EC2Launch.

  • If you previously enabled CloudWatch integration on your instances by using a local configuration file (AWS.EC2.Windows.CloudWatch.json), you can configure the file to work with the SSM Agent on instances created from Windows Server 2016 and later AMIs.

Other differences

Note the following additional important differences for instances created from Windows Server 2016 and later AMIs.

  • By default, EC2Launch does not initialize secondary EBS volumes. You can configure EC2Launch to initialize disks automatically by either scheduling the script to run or by calling EC2Launch in user data. For the procedure to initialize disks using EC2Launch, see "Initialize Drives and Drive Letter Mappings" in Configure EC2Launch.

  • If you previously enabled CloudWatch integration on your instances by using a local configuration file (AWS.EC2.Windows.CloudWatch.json), you can configure the file to work with the SSM Agent on instances created from Windows Server 2016 and later AMIs.

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