Prevent Users from Performing Certain Actions
You can manage user interactions with your spreadsheets by monitoring and responding to events. Events, as the term suggests, are actions that occur as you work with your workbooks and worksheets. Some of the more common events include opening a workbook, saving it, and closing it. You can tell Excel to run some Visual Basic code automatically when any one of these events is triggered.
Users can bypass all these protections by disabling macros entirely. Click the Office button and choose Excel Options → Trust Center → Trust Center Settings and press the Macro Settings Button (pre-2007, Tools → Macro → Security). If their security is set to "Disable all macros with notification" (Medium in pre-2007 versions), they'll be notified of macros in the workbook upon opening it and will be offered the opportunity to turn them off. A security setting of "Disable all macros without notification" (High in older versions) will simply turn them off automatically. On the other hand, if using the spreadsheet requires the use of macros, users might be more likely to have macros turned on. On Mac OS X, you cannot control macro protection at this level of detail. Instead, you can select Excel → Preferences → Security and toggle the setting "Warn before opening a file that contains macros."
