Hi there, give these steps a try:
1. Open up the MacOS System Preferences and click on the option called "Security and Privacy"
2. Click on the "Privacy" tab.
3. Click the padlock in the bottom left and enter your administrator password when prompted
4. In the scrollable list on the left-hand side, click on "Full Disk access".
5. If Photo Mechanic 6 is not in the list on the right, go to step 6. If Photo Mechanic 6 is in the list on the right-hand side, check the box next to it. Close the window and restart Photo Mechanic.
6. Click the Plus button under the list on the right-hand side.
7. Find Photo Mechanic 6 in the Applications folder and click Open. Make sure the box next to it is checked in the list on the right-hand side and then close the window and restart Photo Mechanic.
I have attached a screenshot with the relevant System Preferences window.