SQL Server: Insufficient access rights error when doing backup

All of sudden SQL Server Management studio gives me the following error message when I'm trying to browse for the backup file location.

Property BackupDirectory is not available for Settings 'Microsoft.SqlServer.Management.Smo.Settings'. 
This property may not exist for this object, or may not be retrievable due to insufficient access 
rights.  (Microsoft.SqlServer.Smo)

SQL Server was installed on the server by Plesk control panel which might the part of the problem. Anyway, this can be fixed by adding BackupDirectory registry key that points to default backup directory. For example, if you are in the default SQL instance, create the "BackupDirectory" string value under [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQLServer] and in the value itself put the complete path for the default backup directory you want. To be on the safe side add the same key to [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQLSERVER] branch as well.