Error: User does not have permission to perform this action.
Description: When trying to run Transact-SQL statement like DROP, GRANT, EXEC etc for which the logged in user do not have the permission to perform or execute this statement, the exception throws up. Sometimes while trying to access database system objects, the exception throws up.
Solution: First check whether the log in using to connect and perform database activities exists or not. Open SQL Server Management studio, under Security, Logins node add the user and map the database also. Or, if the user already exists then GRANT required permission’s.