At the beginning of this lesson we mentioned the feature called Trust all installed add-ins and templates. (An add-in is a supplemental program that adds custom commands or custom features to Microsoft Office System programs.)
The Trust all installed add-ins and templates check box is selected by default in the Trusted Publishers list in the Security dialog box.
The macro security levels described in the previous section interact with this feature. For example, even if your macro security level is set to Very High, when the Trust all installed add-ins and templates check box is selected, all installed add-ins will be trusted. Macros in the XLStart folder will also be trusted, but only when you start Excel.
What does this mean to you? To reduce your computer's vulnerability to malicious macros, you should clear the check box for Trust all installed add-ins and templates. Otherwise, macros and add-ins in the folder mentioned above will be run without you being asked.
Clearing the check box for Trust all installed add-ins and templates doesn't mean that you'll have constant security warnings about Microsoft-issued macros. That's because on the first warning you can choose to accept Microsoft as a trusted publisher.
For a complete summary of the various settings, see the Quick Reference Card.
Note If you are a big macro user and you don't want to be bothered by security warnings, you can create a digital certificate for yourself so that macros that you create will be trusted. For more information, see the Quick Reference Card.