Mastercam posts are written in a proprietary scripting language. Most shops eventually hire a Post Processor Specialist or pay their Mastercam Reseller for customization services.

“A toolpath without a post is just a beautiful ghost.”

If the post is from an older version of Mastercam, use the Migration Wizard (File > Convert > Post Wizard) to update the logic to your current version. Tips for Safe Implementation

Powerful but user-unfriendly. The download itself is safe and free for basics, but don't expect to run complex machines without paying your reseller for a proper post.