Microsoft-outlook

Outlook is designed to help protect your computer from viruses and junk e-mail messages. The following information focuses on the virus protection features in Outlook.
Macro security
Outlook itself cannot detect whether a virus is present. Macro viruses are spread through attachments, not the e-mail message itself. Microsoft Office achieves macro virus protection by using the High macro security setting as the default. With the High setting, you can run only digitally signed macros from trusted sources or macros that you created yourself, as long as the installed add-ins and templates are trusted. Unsigned macros are automatically disabled.
Note Signing a macro is similar to getting a legal document notarized by a legal authority or getting your passport stamped by a government official. Electronic certificates are used to sign the macro code. Certificates are issued by a certificate authority, such as a bank, government, or software company, which should be trusted sources. For example, all macros that are pre-installed with Office are signed by the developers who created them using certificates issued by Microsoft that vouch for their authenticity.
If you change the macro security level to the less secure Medium setting, you automatically receive a warning each time you open a document that contains a macro. You can select an option in the Security Warning dialog box about whether to run the macro. Disable Macros is the default button.
Note If the security setting is set to Low, Outlook will not warn you before running a macro. Therefore, all macros are run automatically without your intervention. Because of the potential security risk, Microsoft does not recommend that you use the Low setting.