Try these 2 way and share if it works...

1st way

USE master

CREATE LOGIN [NT AUTHORITY\SYSTEM] From Windows with default_database = [master], DEFAULT_LANGUAGE=[us_english]

2nd way

If this account is missing under Security/Logins then please add the login by the following syntax:

sp_grantlogin 'NT AUTHORITY\SYSTEM' if this fails then try this sp_grantlogin '[NT AUTHORITY\SYSTEM]'

then

make sure the default database for ' NT AUTHORITY\SYSTEM ' login is master.

then

Go to 'Security->Logins' in Management Studio, open the properties window of ' NT AUTHORITY\SYSTEM ' login, at the 'User Mapping' tab, map the appropriate database and select the required database role for each database.

Sanjiv

HTH