Macro virus protection

A macro virus is a macro that can do some damage to a workbook such as overwrite text or delete sections of data - when you perform an action that triggers the macro to run. Most macro viruses also spread to other workbooks on your computer or network, and if you don't realize you have one, you can unknowingly send it to others in e-mail and infect their computers.

Because macro viruses spread so easily, Excel has protection built in that warns you if a macro is present before you open the file. This is a good thing that's also very annoying because Excel can't distinguish between dangerous macros from computer crackers and your own benign macros.

Fortunately you can change the macro security settings to suit your comfort level. To change your security setting, click the Security button on the Visual Basic toolbar (or choose Developer tab> Code Group> Macro Security), click a security level and click OK.

• Disable all macros without notification: All macros not in a trusted location are automatically disabled. You can consider this a very high security setting
• Disable all macros with notification: This setting will disable all macros not in a trusted location, but with notification to you.
• Disable all macros except digitally signed macros: All macros are disabled that are not digitally signed.
• Enable all macros: This is the lowest security setting; all macros will run regardless of digital signatures.