Some filenames or folders can appear in NT that cannot be removed, created, copied, or moved by any NT internal commands. These can include any internal NT device names: (this is not meant to be a full list)

(LPT1-9--LPT1, LPT2, etc), PRN, CON, AUX, NUL, (COM1-9--COM1, COM2, etc)  [...]

To remove these files from NT:

Del \\.\Drive:\directory\filename

Example: Del \\.\c:\someplace\lpt1

OR:

Use a POSIX utility:

rm "filename"

Example: rm com1

or if a folder: rmdir "folder name"

Example: rmdir lpt1

OR:

Delete from a Mac through the mac folder that maps to the NT SFM Volume

Mac users should try not to create files with these names.