In computing, Normal.dot is one of the most important files in Microsoft Word. It is the master template from which all Word documents are created. It determines the margin defaults as well as the layout of the text and font defaults.
User errors
Although normal.dot is already set with certain defaults, the user can change normal.dot to new defaults. This will change other documents which were created using the template, usually in unexpected ways.
References
Normal.dot Wikipedia(Text) CC BY-SA