Lets say I need to map folder C:/D as drive D:

One can use SUBST command to map folder as drive in Windows.

SUBST d: C:/D

I am absolutely happy how SUBST does the work. So I set this command as a startup task using the task manager.

A problem here is that if I have a flash in a USB port while booting Windows, the flash is got mapped as D: and SUBST fails.

The question is how to make C:/D to be D: permanently. So other drives (especially flash drives) don't break this during startup.

P.S. I know I could set D: to be R: which is unlikely to conflict with other drives. But I would greatly appreciate another answer.