コマンドプロンプトとdiskpartツールで削除
> diskpart
DISKPART> list disk
DISKPART> select disk N
DISKPART> list partition
DISKPART> select partition N
DISKPART> delete partition override
DISKPART> exit
> exit
> diskpart
DISKPART> list disk
DISKPART> select disk N
DISKPART> list partition
DISKPART> select partition N
DISKPART> delete partition override
DISKPART> exit
> exit