1069 error (unable to start the service due to login failure) Solution

The reason is very simple. When installing SQL Server, the default login user is used as the account for starting the SQL Server service (the Administrator is usually used for standalone servers ), when the user changes the user name (for example, someone prefers to change the Administrator to admin) or the password, the "cannot start service due to logon Failure" error occurs again when the server is restarted.
After knowing the cause, the solution is clear.
1. Change the user password back to the original one, and then start the service.
2. Use the Service Manager of the Control Panel to find the MSSQLServer service, change the startup account information, change it to the changed one, and then start the service.
3. It is also recommended to create a new user dedicated to starting the SQL Server service. This user is used to start SQL Server when installing SQL Server, this avoids the 1069 error caused by frequent changes to the administrator password. If you have installed SQL Server, you can also change the service account information of the MSSQLServer service under the service manager of the Control Panel to a user dedicated to the SQL service.