How do you fix app is damaged and can't be opened on Mac?
Open the Apple menu > System Settings. Select Privacy & Security > Developer Tools. Click the ( + ) button and navigate to the folder where the damaged app resides. Select the app and click Open.
How do you fix a damaged file on Mac?
Mac's Built-In Repair Shop
Open up your Applications folder, and click “Utilities.” Open up the Disk Utility application in that list to have access to the repair tool. Now simply drag your damaged DMG file onto the Disk Utility window. Click the damaged file, and then select “Repair Disk” in the First Aid tab.