Hi SQLRNNR & Bill

Thanks for your replies issues is partially solved here i'am giving description and also can you please suggest why it is solved ?

1. we didn't find any root cause and errors from any side but after deep monitoring in the server from wintel steam had updated firmware later from DB end i tried to take backup manually to check whether the server is rebooting now also.. but the one of the database backup is executed and in the properties of the job we find the owner has changed and by comparing the job which has success we changed and tried to take backup then it also executed [these two databases are user databases ]

2. in system database[master.model,msdb] maintenance plan backup jobs are continuesly failing even after checking all the permissions correct

1. then i disabled the current one and created a duplicate backup

maintenance plan and tried to execute it went success and the .BAk files is available for current time similarly created for every one and scheduled also whether its working or not ... it is succeeded

2. deleted all jobs and freshly created and checked its working and

now it is under monitoring for few days

3. can any one say why it got succeeded and what is the actual cause because i want to know the root cause.

"some times right things get wrong and wrong one clicks "