AUX, CON, NUL, SMS and PRN are reserved names in Microsoft Windows.
Not possible to create folder using above names expect SMS. SMS name is used in System center configuration Manager.
Example: Default Collections ID are starts with SMS.
Microsoft does not recommend that you used these names as site codes when you install Microsoft System Center
Configuration Manager. This includes SMS 2003, SCCM 2007, CM 2012, or any versions of System Center Configuration Manager (Current Branch).
Several SMS and Configuration Manager Components use the site code as a folder name, and because these names are
reserved names in Windows, folders cannot be created with these names.
These names are reserved in all versions of Windows.
Although you may not experience a problem when you install SMS or Configuration Manager and designate these site
codes, you may experience problems later.
Site code is used to uniquely identify the Configuration manager site in the hierarchy.
The following rules apply when we define the site code.
1. Use Alphanumeric site codes letters [A-Z], number [0-9] Example : A00
2. Do not use Microsoft reserved names such as AX, CON, NUL, or PRN
3. Setup does not verify that the site code entered is not already in use.
4. Changing the site code or site name after installation is not supported.
5. Do not re-use site codes.