Macro Viruses Setting Security Levels in Office Applications Microsoft Word, Microsoft Excel, and Microsoft PowerPoint can be set to a high, medium, or low security level. High security Macros must be signed by a trusted source. Otherwise, macros in documents are automatically disabled without notice when the documents are opened.
Word is set to the high security level by default.
Medium security Users are prompted to enable or disable macros in documents when the documents are opened. Excel and PowerPoint are set to the medium security level by default. No macro checking is performed when documents are opened and all macros are enabled. This security level is not recommended because no protection is active when it is selected. On the Tools menu, point to Macro , and then click Security .