原文：https://stackoverflow.com/questions/10815975/sqlexpress-local-database-administrator-password
In your client (SQL Server Management Studio) you have to:
- change password for login user "sa"
- enable login for user "sa"
- ensure SQL Server authentication is enabled
1. change password for login user "sa"
Security > Logins > sa (right-click) > Properties > General > Password and Confirm password
2. enable login for user "sa"
Security > Logins > sa (right-click) > Properties > Status > Login, click in Enabled
3. ensure SQL Server authentication is enabled
Right click on server > Properties > Security > Server authentication, click in SQL Server and Windows Authentication mode
标签：Express,Server,user,Sql,login,sa,password,click From： https://www.cnblogs.com/lookforFree/p/18420489