Have you ever tried creating a folder starting with a dot "." or ending with a "." ?
Just create a new folder in Windows with any of the following names..
1. NUL
2. CON
3. PRN
4. AUX
5. LPT1 to LPT9
6. COM1 to COM9
Since these are the reserved keywords of Windows OS, we are not able to create folders with these names.
Just reply to this post if a folder is created with the above names ;-)