This topic describes the issue that you are prompted to activate the Windows service after you migrate a Windows server by using Server Migration Center (SMC). This topic also describes the causes of and solutions to this issue.

Description

You are prompted to activate the Windows service after you migrate a Windows server.

Causes

After you migrate a Windows to Alibaba Cloud, the Windows serial number becomes invalid due to underlying hardware change. You must reactive the Windows service before you can use the server.

Solutions

Connect to the Windows instance.
On the Microsoft Key Management Services (KMS) client activation and product keys page, find your Windows KMS client key. Example: xxxx-xxxx-xxxx-xxxx-xxxx.
Open the CLI as an administrator, and run the following commands:
```
slmgr /upk
slmgr /ipk xxxx-xxxx-xxxx-xxxx-xxxx
```
Use KMS to activate the Windows service. For more information, see How do I use KMS domain names to activate a Windows instance in a VPC?