SQL server2014 failed to delete the database, with an error offset of 0x0000

SQL SERVER Mounted on D disc , In restoring the database E10SYR when , Select to restore the database files and logs to G（ mobile hard disk drive ） Of 1,2

Has been manually G（ mobile hard disk drive ） Of 1,2 Deleted , Now I want to SQL SERVER Delete E10SYR, Has been an error

The following statement will not run either ：
use master
go
alter database database_name set single_user with rollback immediate
-- Rollback the database to the original configuration state
go
drop database E10SYR -- Delete database
go

ALTER DATABASE E10SYR SET OFFLINE WITH ROLLBACK IMMEDIATE
ALTER database E10SYR set online

How can I delete this database