Error 1069 occurred when SQL Server started: Failed to start due to logon failure

Workaround:
(1). My Computer--control Panel--management tool--service--right-click mssqlserver--Properties--Login--Login identity--select "Local System Account".
(2). My Computer--control Panel--management tool--service--right-click mssqlserver--Properties--Login--Login status--select "This Account"--Enter your modified administrator password in the password and Confirm password.

The difference between the two:
Choose the first way, later modified the administrator password, no longer adjust (but require to log on the operating system is the system administrator).
Choose the second way, later modified the administrator password, but also repeat the above operation.

(3). Turn on Computer Management, create a new user SQL Server password of 123 (which can also be something else), and then add SQL Server to the Administrators group (or not enough permissions or not). Then from the management tool into, find the service, right-MSSQLSERVER, properties, then open the Login tab, browse, find SQL Server, enter 123, OK. This way, we won't be able to start the service because of a login failure because of changes to the administror.

Error 1069 occurred when SQL Server started: Failed to start due to logon failure