Hey AlexandruTimar,
Nah, that's just a WinRE (Windows Recovery Environment partition) brought into view in 1803, it's usually hidden. You cannot remove, but only you must remove its mapping of its respective drive letter, which is F. Once you do this, it brings it back to its intended visibility, being hidden and out of sight. Once you do this, you won't be pestered with low disk space notifications anymore. You will need to remove the drive letter and mount point in DiskPart in order to do this.
Hit Windows key + R together to go into Run. Type in the following: diskpart
Enter the following in the new DiskPart window:
select volume F
remove letter=F
Does not work after a reboot? Try entering this instead in an administrator session of Command Prompt: mountvol F: /D
Source: https://www.reddit.com/r/Windows10/comments/8gj...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
I hope this helps. Please do let me know if this fixes it, and good luck.