Hide or Dismount a Partition with Disk Management Utility in Windows

Secure or hide your personal drive data from unwanted access by hiding it
The tutorial guides you how to hide your personal data or tools (on a particular drive) on a system with multiple operating systems installed or on a system with multi-user access. You can do this through Computer Management or the Command Prompt. You will also learn how to unhide or mount it back, when you need it.
Note: When you hide it this way, it will never show again until you unhide it manually. It works in all the versions of Windows.
Part 1: Hiding (dismounting) the partition from Disk Management

Step 1: Open the Disk Management utility by right clicking on My Computer > Manage > Disk Management. A list with all the partitions existing in your computer will show.

Step 2: Right click on the partition you want to hide (dismount) and select Change Drive Letter and Paths.

Step 3: In the Change Drive Letter and Paths window, click on the Remove button. You are asked to confirm the removal of the drive letter. Click Yes.

NOTE: Make sure you close all the applications that might be using files from that partition and then click Yes, to continue the drive letter removal operation otherwise you may get a warning as shown in the screenshot.
Now, the partition is hidden or dismounted and no user can access it. Every time one logs in, Windows recognizes the setting and the partition never shows until and unless you manually unhide it.

Part 2: Hiding (dismounting) the partition from the Command Prompt
Step 1: The above process and its result can be achieved by using a simple command on Command Prompt. First, right click on Command Prompt and run it as administrator. Type the following command: mountvol drive letter /D. Replace the drive letter text with the actual letter of the drive you want to hide (dismount). We have hidden the partition is ‘E’, so the command is mountvol E: /D. The /D argument stands for dismount.

Part 3: Unhiding the partition from Disk Management
Step 1: If you want to unhide (mount) a partition, open Disk Management as shown in part 1. Then, select the drive you want to unhide, right click and select Change Drive Letter and Paths.

Step 2: In the Change Drive Letter and Paths window you will see that there is no drive letter assigned to the partition. To make it visible again, it needs a drive letter. Click the Add button.

Step 3: From the, Assign the following drive letter, drop-down box, select the drive letter you want to assign. When done, click OK.

The partition is now visible again and anyone can access it.
Part 4: Unhiding the partition from the Command Prompt
Step 1: Run Command Prompt as administrator and type mountvol/?. You will first see a list of all mount and unmount volumes or partitions.

The entries with text NO MOUNT POINTS represent hidden (unmounted) partitions, which can be unhidden (mounted) again.

Step 2: To mount a partition type: mountvol drive letter VolumeName. The text drive letter should be replaced with the letter you want to use (e.g. D: E: F:). Make sure you assign drive letters which are free and not taken by other partitions. VolumeName should be replaced by the text which starts with “\?Volume{“.
Note: The command is case sensitive - using the wrong case even for one letter, will cause the command to fail.
The partition simply shows up in Windows Explorer, if the command is executed successfully without any
error message.

Note: This activity should be exercised very carefully. PCQuest will not be held responsible if the user loses data or damages anything because of this.