Upgrading an Amazon EC2 Windows instance to a newer version of Windows Server

There are two methods to upgrade an earlier version of Windows Server running on an instance: in-place upgrade and migration (also called side-by-side upgrade). An in-place upgrade upgrades the operating system files while your personal settings and files are intact. A migration involves capturing settings, configurations, and data and porting these to a newer operating system on a fresh Amazon EC2 instance.

Microsoft has traditionally recommended migrating to a newer version of Windows Server instead of upgrading. Migrating can result in fewer upgrade errors or issues, but can take longer than an in-place upgrade because of the need to provision a new instance, plan for and port applications, and adjust configurations settings on the new instance. An in-place upgrade can be faster, but software incompatibilities can produce errors.