Windows 10 v1803 April 2018 The update brought many new and improved features. However, many users have reported that it creates additional OEM or recovery partitions . It is essentially a WinRE partition. They cannot be deleted immediately because they are assigned a logical drive letter.
This excess partition is visible in both File Explorer and Disk Management and occupies (at least virtually) disk space. In some cases, the system starts with the message that the disk is full. Also, when you check the disk usage in Task Manager, you can see that it is approaching 100%, which slows down the system.