Basically CON, PRN, LPT1, LPT2, LPT3 are folders which are reserved by Windows, you can't create it easily. So if you want to create any folder with these names then follow these simple steps:
- Make any folder with any name.
- Rename the folder and name it CON
- Press & hold Alt key & type 0160
- Leave Alt key now.
Using it, you can make any folder with these names.
