Drive appears in my computer but doesn't exist

OP did say that he has only one new drive with the letter E:, which is in this case only named RAID, I assume.

The AutoCAD (Autodesk) installation shouldn't be something more than the usual software installation. It should usually be done through a USB or DVD and the process is described here:

Installing & Configuring Software on a Single Computer with a Stand-Alone License | Installation, Activation & Licensing | Autodesk Knowledge Network

But also, it's great that OP mentioned the subst part, that explains a lot, if not everything. If he had to use a virtual disk for the installation, or the system decided that the CD/USB can be mounted virtually, working with the subst-command is where everything got wrong. At least, this is what I assume.

So following @Pauly's logic, which I think is correct, specifying the path to the virtual "ghost" drive like

subst F: /d

should delete it!

The only thing that's personally bothering me is that the system created a virtual copy of the OS drive. I am not quite aware of how things would proceed, but I think some sort of check up should be made to see if deleting the ghost OS drive won't affect the real C: drive?

Just thinking out loud.

CK_WD

Okay, you deleted the virtual drive, that's good, but the path to it is still active somehow. I would suggest you first try and delete permanently (until you assign it again) the F: drive letter, using this link with the command line:

https://www.microsoft.com/resources/....mspx?mfr=true

Although, the subst command should have deleted it along with the drive.

Then, the error code 1327.
It occurs when installing such a demanding software as Autodesk. The reason as explained would be either "A system folder is mapped to a network drive that has the Reconnect at Logon check box checked" or "You've changed the drive letter for the CD-ROM drive or hard drive where the system folder is located".

In the link below are given a few options on how to fix this problem when happening during Autodesk installation.

Error 1327 invalid drive | AutoCAD | Autodesk Knowledge Network

Hope any of these help!

CK_WD

Check network places to see if you still have any active mapped drives