Windows 10 v1803 April 2018 Update brought along a lot of new features and improved upon existing ones. However many users reported that it creates extra OEM or Recovery partition. It is basically a WinRE partition. They cannot be deleted straight away since they have a logical drive letter assigned to them.
This surplus partition is visible in the File Explorer as well as Disk Management and occupies disk space (at least virtually). In certain cases, the system starts with the notification that the disk is full. Moreover, upon checking Disk utilization in the Task Manager, you may find that it is almost nearing 100%, thus slowing down the system.
Windows 10 v1803 creates an extra Disk Partition
To fix the issue, try the following suggestions:
1] Hide the logical drive
The drive is necessary to recover Windows 10, but it virtually occupies space. We could hide the partition so that it doesn’t appear in File Explorer.
However, if you actually want to remove the extra partition, it isn’t possible through Disk Management. They don’t show the option for the same. You may need to follow these suggestions.
2] Using third-party software to delete it
While the Disk Management might not work, third-party Partition Manager software will be able to help you delete the partition.
3] Use Diskpart
You could use an elevated Command Prompt instead of Disk Management to shrink/remove the extra partition. Execute the following commands:
select volume <the volume in the drive>
Here X: is the Drive letter.
This step will remove the surplus partition and resolve the issue.
4] Remove the MountPoint
Right-click on Start and select Command Prompt (administrator).
Type the command mountvol X: /D and press Enter, where X: is the Drive letter.
Hope this works for you.