Setup crashes when encountering a substitute drive #52

Describe the bug
Setup fails to install if there any any substitute/virtual drives with the message: Invalid Drive: X:\
I guess this isn't a bug with the driver itself but more of the setup, but I couldn't find a repository for that.

To Reproduce

1. Create a substitute drive, e.g. subst X: C:\SomeFolder
2. Run the setup
3. See the error message box appear when the status "Computing space requirements" is shown

Expected behavior
The setup shouldn't crash when trying to compute space requirements for substituted drives

Screenshots

System details (please complete the following information):

• OS: Windows 10 Pro (18363)
• Driver Version: 1.16.116

Workaround
A simple workaround is simply to delete the substituted drive with e.g. subst /D X: but this is undesirable.