I am guessing this issue is due to the Security and Privacy settings in MacOS. Here are the steps to give Photo Mechanic the access it needs:
1. Quit out of Photo Mechanic 6.
2. Open up the macOS System Preferences and go to "Security and Privacy".
3. Under the Privacy tab, select 'Full Disk access' on the left hand side.
4. Click the padlock in the bottom left to unlock it.
5. Enter your administrator password to be able to make changes.
6. Find Photo Mechanic in the list on the right and check the box next to it (if Photo Mechanic is not in the list, select the + sign under the window and add it from the Applications folder).
7. Close the System Preferences window.
If that doesn't solve the issue, please send a Log file as requested by Kirk.