When I got my MacBook Pro I was excited about the possibility of using my iMac as an external display using Mini DisplayPort or ThunderBolt cables. Unfortunately, my 21.5″, late 2009 iMac does not support video-in.

Here’s a link to Apple’s info on target display mode so you can find out if your configuration will support using your iMac as an extended desktop for your MacBook Pro:

https://support.apple.com/en-us/HT204592

My solution (for now)

In my case, I wanted to use both the iMac and the MacBook together so I can sometimes make use of the bigger screen and mouse of the iMac (for example, when I’m using Photoshop). For a while, I was using them independently and I found it was a pain to keep all my files organized.

Now I use file sharing and I set it up so that the iMac connects automatically. My main work folder is on the MacBook and shows up as a shared drive when I login to the iMac.

Here’s how it works

Set up file sharing on the MacBook:

1. Go to “System Preferences”
2. Click on “Sharing”
3. Under “Shared Folders” list click the plus button
4. Navigate to the folder you want to share with your iMac
5. Click the “Add” button in the bottom right
6. The folder will be added to the list of shared folders
7. Set the desired permissions in the”Users” list
8. Close “System Preferences”

On the iMac, connect to the MacBook:

1. Select the MacBook Pro under the Shared items in the left side of a finder window
2. Click the “Connect As…” button
3. Connect as “Registered User” and enter the Name and Password you use on the MacBook Pro
4. Select the checkbox for “Remember this password in my keychain”
5. Click “Connect”

Set up login on the iMac:

1. Go to “System Preferences”
2. Click on “Users & Groups”
3. Click the “Login Items” tab at the top
4. You will see a list of items that will open automatically when you log in
5. Click the plus button at the bottom
6. Navigate to the shared item (it will be the name of your MacBook Pro)
7. Select a the folder you want to mount automatically on login
8. Click the “Add” button in the bottom right
9. The folder will be added to the list of log in items (don’t check the “Hide” checkbox if you want to see the shared folder as a drive on your desktop)
10. Close “System Preferences”

Now when you’re logged in to your MacBook (I usually work with my MacBook on the desk next to the iMac) the iMac will automatically connect on login. If you’re already logged in to the iMac and they’re not connected, you can quickly connect by typing Command + K and clicking the “Connect” button (you won’t need to enter your password).

You may have frustrations connecting from time to time. Try logging out/in or restarting to resolve the problem.

To-do: figure out how to use the terminal on the iMac to use git repo tracking a directory on the MacBook. It currently works, but it’s super slow. If anybody knows how to do this, please let me know.