We are running SQL server 2005 standard Edition. We are using a separate instance for the concerned database. Following the first instillation some maintenance plans for backup were created. After that I forgot the SA password and had to reset after login using windows authentication. After that I tried to delete these maintenance plans but could not. When I attempt to delete them I get the following error message Exception has been thrown by the target of an invocation. (mscorlib) Additional information Login failed for user SA (Microsoft SQL server; error 18456) It is kind of weird because I am able to use the new password for SA. Any help would be much appreciated.