After AD promotion, sql server agent cannot start with error message:
"No mapping between account names and security IDs was done. [0x80070534]." .. or whatever..
For this case. you cannot to change the account used by the SQL Server services via SQL Server Configuration Manager since it is trying to resolve the SID of the old account to the name of the user, and can't do it.
To solve the problem, go to the Windows Services applet (services.msc) and use that to change the account used by the service. For the service to function properly the new account would have to be one that you know has enough privileges. Or just change it to any user that exists, and then go back to Configuration Manager (which will hopefully work now) and change it again, so that the privileges are set correctly.
