Starting with Windows 10 1903, Microsoft introduced Reserved Storage which allocates a portion of the disk for upcoming updates and fixes. The presence of extra space reserved for cumulative updates resolves several bugs that occur due to not enough storage.…

Reserved Storage is a new concept, all set to come with Windows 10 19H1 update. As its name suggests, this will block 7 GB of the regular Disk space for the purpose of System Update, temporary files, and cache.