This is a little information about VBA Macro Security:

In Microsoft Excel, you can change the macro security settings to control which macros run and under what circumstances when you open a workbook. For example, you might allow macros to run based on whether they are digitally signed by a trusted developer. The following list summarizes the various macro security settings. Under all settings, if antivirus software that works with 2007 Microsoft Office system is installed and the workbook contains macros, the workbook is scanned for known viruses before it is opened.

Disable all macros without notification: Click this option if you don't trust macros. All macros in documents and security alerts about macros are disabled. If there are documents that contain unsigned macros that you do trust, you can put those documents into a trusted location. Documents in trusted locations are allowed to run without being checked by the Trust Center security system.

Disable all macros with notification: This is the default setting. Click this option if you want macros to be disabled, but you want to get security alerts if there are macros present. This way, you can choose when to enable those macros on a case by case basis. Disable all macros except digitally signed macros: This setting is the same as the Disable all macros with notification option, except that if the macro is digitally signed by a trusted publisher, the macro can run if you have already trusted the publisher. If you have not trusted the publisher, you are notified. That way, you can choose to enable those signed macros or trust the publisher. All unsigned macros are disabled without notification.

Enable all macros (not recommended, potentially dangerous code can run): Click this option to allow all macros to run. Using this setting makes your computer vulnerable to potentially malicious code and is not recommended.

Trust access to the VBA project object model: This setting is for developers and is used to deliberately lock out or allow programmatic access to the VBA object model from any Automation client. In other words, it provides a security option for code that is written to automate an Office program and programmatically manipulate the Microsoft Visual Basic for Applications (VBA) environment and object model. This is a per user and per application setting, and denies access by default. This security option makes it more difficult for unauthorized programs to build "selfreplicating" code that can harm end-user systems. For any Automation client to be able to access the VBA object model programmatically, the user running the code must explicitly grant access. To turn on access, select the check box.