The SQL Server service won't start. When trying to start it manually, it says there is a logon failure.
Apart from the password of the account running that service being wrong, this can also be caused by a change affecting account trust, such as joining/leaving a domain.
- Open the Services snap-in (services.msc)
- Right-click the SQL Server service for the desired MSSQL instance, and click Properties
- Open the Log On tab
- Do one of the following and click OK:
- If the account being used is "NT Service\MSSQLSERVER", blank out both the Password and Confirm password fields, and click OK
- Provide the credentials of another account with local administrator permissions, and click OK
- Start the desired SQL Server service