The Macros in this Project Are Disabled
If you get this alert message in PowerPoint while trying to run a Macro or Macro Enabled Slideshow: “The Macros in this Project Are Disabled” in PowerPoint, then you will need to enter PowerPoint Options and then Trust Center. Here you can disable all macros except digitally signed ones, or enable all macros. Notice that this option is not recommended but if you trust in your own files then you can safely enable it.
If you choose to disable all macros except digitally signed ones, then you can sign your Macros in Tools menu. Here you have a screenshot showing the Digital Signature menu.
If you need detailed information about this topic, you can refer to the official Microsoft KB center.