When you connect an external storage drive to a Mac, it mounts automatically. You then have to double-click it to open it in Finder. It’s nothing too difficult but if you want to automatically open Finder on disk mount, you can create a folder action with Automator. It will open the mounted disk and show its contents in Finder. Here’s what you need to do.
Automatically open Finder on disk mount
Open Automator and create a new document. In the document type selection panel, select Folder Action.
Once you’ve done that, you will see a dropdown at the top called ‘Folder Action receives files and folders added to’. Open the dropdown, and select Other. Next, tap the Shift+Command+G keyboard shortcut. You will see a new panel. In this panel, enter the following, and click Go and then Choose.
The final step is to look for the ‘Open Finder Items’ action from the column on the left. You can use the search bar at the top to look for it. Drag and drop it on to the pane on the right, and go ahead and save the action. Give it a name that tells you what it’s for.
Next, connect your drive. It will mount automatically, and you will see a prompt telling you ‘FolderActionsDispatcher’ would like to access the files and folders on the volume. Allow it to do so. This prompt won’t appear every time.
If you ever want to remove the folder action, you need to go to the following location.
Here, look for a script called Remove Folder Actions.scpt. Double-click it to run the script, and then select the folder action that you want to remove. You won’t have to remove all folder actions. You will have the option to choose which ones to keep, and which one to get rid of.
This will work for all drives and anything else that macOS recognizes as a drive. This means that apps that are distributed as DMG files, and mounted will also likely open in Finder. This is useful but be warned that it might also pose a security risk. That’s why macOS doesn’t have this feature out of the box. A volume might have something malicious in it that runs when it is accessed. Mounting it doesn’t allow anything to run, but opening the drive in Finder might trigger the malicious content, whatever it is, to run. The point is, be careful with this.