When you save a file using the common Save As dialog, the file may use a generic Windows icon, without a file extension.
If the name that you used exceeds the operating system maximum number of characters, you will experience this feature.
The solution is to rename the file to a shorter name, and to use shorter names when saving the file.
Typically, the entire path to the file cannot exceed 255 characters, including spaces, and the file name cannot contain the following:
\ / : * ? < > |