How to back up Airmail app?
1. In Finder, open the ‘Applications’ folder and find 'Airmail.app’.
2. Hold 'Option’ (or 'Alt’) and drag Airmail.app to your Desktop or another folder.
3. Right click the copied version of Airmail and select 'Compress “Airmail.app”’
4. The file 'Airmail.app.zip’ will be made, if you want you can move this to another folder or hard drive.
Important: Do not remove Airmail from your Applications folder, make sure you copy the backup (or hold option and drag).
How to back up Airmail Data?
To backup Airmail data at any time, you can “copy” but do not move this location.
1. Please go to Finder and press Shift+Command+G and the following box will appear.
2. Type this command
3. Copy and paste the contents elsewhere(the place where you want to save the back up) but do not move them.