All Postbox settings and data are stored in a data folder that resides outside of the application. You can transfer your Postbox data folder from one machine to another by following these instructions:
- Make sure that Postbox is installed on both the "SOURCE" and "TARGET" machines.
- On the SOURCE machine, open Postbox, and from the Help menu select Troubleshooting, then select Reset Caches and Search Index and Reset IMAP mail databases and Search Index.
- On the SOURCE machine, open Postbox, and from the File menu select Compact Folders. Wait 10 minutes.
- Quit or exit Postbox on both machines.
- Next, move the Postbox data folder from the source machine to the corresponding location on the target machine. The data folders are located here:
- macOS: ~your home folder/Library/Application Support/PostboxApp
(Note: In macOS the Library folder is hidden. To access it, open the Finder, hold the Option key, then select Library from the Go menu.) - Windows: Users\username\AppData\Roaming\PostboxApp (Note: The AppData folder is a hidden folder. To show it, open a Windows Explorer window and choose "View Tab → Options → View Tab → Show hidden files and folders, then click the Apply button".)
- macOS: ~your home folder/Library/Application Support/PostboxApp
- If you are asked if you would like to overwrite the existing PostboxApp folder on the TARGET machine, click "Yes" or "OK."
- Start Postbox.
IMPORTANT: If the source and target machines have different user names, and if you are using the "Local Folders" or "On My Mac" accounts to store messages or if you are using POP accounts, then the pathing must be adjusted to account for the different user names on both machines.
On the target machine, navigate to Postbox > Preferences | Options > Accounts > [each email account] > Local Storage. Here you will see the user name of the source machine.
Click the "Browse" button and navigate to the correct folder on the target machine.