What does adding a second drive path to a drive do?

Question

What does adding a second drive path to a drive do?

janeintoronto 0

The install file for an old app cannot read drive letters properly and I am trying to install it. I was wondering if adding a drive letter or path to the target drive would do this. Then is says "mount the following in an empty NTFS folder" and I have no idea what this means or how to do it.

MotoX80 37,946 Reputation points

2026-11-08T22:58:48.11+00:00

If the install "cannot read drive letters properly" then why would you think that ANY drive letter would work? I'm not sure what that means.

I would suggest that you share the exact error message that you are getting from the application. Screen snapshots really help so that we can see the actual error.

The name and version of the app that you are trying to install would also be useful.

If you downloaded the install executable from some web site, and that's available to anyone, then we could try to run the install on one our test systems and try to figure out what it's doing. Can you share the site address where you got the install?

1 answer

Your answer

MotoX80 37,946 Reputation points

2026-11-08T22:58:48.11+00:00

If the install "cannot read drive letters properly" then why would you think that ANY drive letter would work? I'm not sure what that means.

I would suggest that you share the exact error message that you are getting from the application. Screen snapshots really help so that we can see the actual error.

The name and version of the app that you are trying to install would also be useful.

If you downloaded the install executable from some web site, and that's available to anyone, then we could try to run the install on one our test systems and try to figure out what it's doing. Can you share the site address where you got the install?

Answer 1

Adding a second drive path does not create a second copy of the drive. It creates another way to access the same volume.

In Windows, a volume can be accessed by:

a drive letter, such as D:\
a mounted folder path, such as C:\MountD\

That means the same drive can appear both as a normal drive letter and as a folder on another drive. Windows calls that a mounted folder or mount point.

For the installer problem, this can help if the app expects a normal folder path instead of handling drive letters correctly. It will not change the actual contents of the drive.

Mount in the following empty NTFS folder means:

create an empty folder
that folder must be on a drive formatted as NTFS
Windows then links that folder to another volume, so opening the folder opens that drive

Example:

target drive: D:\
empty folder on C drive: C:\OldAppDrive
after mounting, C:\OldAppDrive points to the D: volume

How to do it in Disk Management:

Right-click Start and select Disk Management.
Select the volume to which the folder path will be added.
Go to Action > All Tasks > Change Drive Letter and Paths.
Select Add.
Choose Mount in the following empty NTFS folder.
Select Browse and choose an empty folder.
Select OK, then OK again.

Requirements:

administrative permissions
the folder must already exist and be empty
the folder must be on an NTFS or ReFS drive
the volume being mounted must be formatted with NTFS or ReFS

Important:

Do not change the drive letter of a drive that contains Windows or installed apps, because apps might stop working.
Adding a mount path is generally safer than changing the drive letter if the goal is only to give the installer another path to try.

If using the command line, diskpart can do the same:

Open Command Prompt as administrator.
Run diskpart
Run list volume
Run select volume <number>
Run assign mount=<path>

Example: assign mount="C:\Demo Drive"

References: