All eVSM software code is signed with a digital signature issued by DigiCert to confirm our identity and show our users the software is from us. By design the digital signature will get corrupted if the code is tampered with by anyone who does not have access to our signature.
Unfortunately, the digital signature can sometimes get corrupted if the PC or Visio crashes during normal operation, or if the file is edited in older versions of Visio. If this happens, you can use the Restore File, Map Clean, or eVSM Repair function to re-establish the genuine signature.