What is this Storage Partition?

[bamitscon]

So my Windows keeps making a noise every now and then saying my Local Disk D; is almost full, but when i go into the partition it says nothing is in there? wtf is this, how do i make it stop sending me those annoying messages.

https://prnt.sc/jm9175
https://prnt.sc/jm919h

 

[USAFRet]

So my Windows keeps making a noise every now and then saying my Local Disk D; is almost full, but when i go into the partition it says nothing is in there? wtf is this, how do i make it stop sending me those annoying messages.

https://prnt.sc/jm9175
https://prnt.sc/jm919h

That is an after effect of the 1803 April update.
A System partition has mistakenly been given a drive letter.

Remove that drive letter, here: https://community.spiceworks.com/how_to/153261-fix-windows-10-1803-update-new-full-drive-creation