This message may appear when you upgrade to macOS Mojave and launch Photo Mechanic 5 (or earlier). If you select OK, the alert message will disappear, and Photo Mechanic runs as expected. 

Why you see this message: While both 32 and 64-bit applications work on Mojave, future updates, including macOS Catalina, removes 32-bit support and will only run 64-bit applications. The warning message is to let you know that Photo Mechanic 5 is a 32-bit application that will no longer work with future macOS updates. This alert does not mean Photo Mechanic is incompatible with your computer. 

Photo Mechanic 5 is compatible with macOS 10.6.8 (Snow Leopard) to Mojave. Photo Mechanic 5 will not run in macOS Catalina or any future macOS updates.
Photo Mechanic 6 is a fully 64-bit application with great new features.  We offer a 30-day free trial if you would like to check it out. 

This information covers Photo Mechanic version 5.   See what's new in Photo Mechanic 6 and try it free for 30 days.