All pptXTREME add-ins are digitally signed with a authenticated certificate for your saftey.  If your Macro Security is set to High and you do NOT trust all installed add-ins then you may see the following message when PowerPoint® loads after installing a pptXTREME add-in:
 

 
You can see the details on the certificate by clicking on details...

 

In order to use the pptXTREME tools you need to check the box next to Always trust macros from this publisher, then click Enable Macros.

 

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To find out how to change your macro security see this FAQ.

 

For more information about macro security in office applications see this Microsoft® FAQ.