Can’t Alter Login

Question

Check out this link:
Fix a SQL Server Login which has MUST_CHANGE set to ON

You can use the following query to fix that:

USE Master
GO
ALTER LOGIN UserName WITH PASSWORD = 'password'
GO
ALTER LOGIN UserName WITH
      CHECK_POLICY = OFF,
      CHECK_EXPIRATION = OFF;

Replacing UserName and password with the proper values.

The link will also walk you through the process of fixing it in the management studio interface.