Source: Chris Hoffman, HowToGeek.com, April 16, 2018
PC manufacturers often include recovery partitions.
These are usually hidden, but sometimes become visible under This PC and elsewhere in Windows. Here’s how to hide a recovery partition—or any other drive.
We’ll be removing a partition’s drive letter to hide it. The partition will still be visible to disk management tools, but it won’t appear in Explorer and normal desktop applications. You can always reassign a drive letter to it in the future.