How to avoid these dangers? Just follow one simple rule: enable only safe macros – ones that you've written or recorded yourself, macros from trusted sources, and VBA codes that you have reviewed and fully understand. For this reason, Excel's default setting is to disable all macros with notification. A malicious macro that you run unwittingly may damage or completely delete files on your hard drive, mess up your data, and even corrupt your Microsoft Office installation.
Though VBA codes are very effective in automating complex and repetitious tasks, they are a significant source of risk from the security point of view. Before you go enable macros in your worksheets, it's important to understand how dangerous they can possibly be.
