Set default mail client in macOS without adding an email account?

Question

I'm on OS X el Capitan (10.11.6).

I use Outlook to access my email and would like outlook to be the default mail application. All the instructions I find online suggest that I should open mail and choose "Mail -> Preferences" to set the default mail app.

Unfortunately, Preferences is greyed out until an account is added. I don't have another account that I want to add to my Mac.

How can I set the default mail client to Outlook without adding an account to the mail client?

Answer 1

Pre-Catalina
The simplest way to do this - which doesn't involve messing with Mail itself - is the old faithful RCDefaultApp

Post-Catalina
RCDefaultApp no longer works on modern macOS.
The new kid on the block is SwiftDefaultApps

This Preference pane is chiefly intended to be a modern replacement for the amazing RCDefaultApp developed way back when by Carl Lindberg, which stopped working in 10.12 due to deprecation of ObjC Garbage collection.

It installs as a control panel from where you can set defaults for just about anything on the machine... including Mail.

Simply select from a drop menu

---

Old version, for pre-Catalina...

If you want to have a poke at the other sections, note it can take some time to build the apps/services list; don't think it's hung, it's just thinking ;-)

Answer 2

Update: Seems like Microsoft finally removed this tool. The suggested solution in their support documentation is

https://support.microsoft.com/en-us/office/set-an-account-as-the-default-in-outlook-for-mac-1a085d36-db97-4230-9a40-c332364426e0

I finally found something easy that worked, the SetDefaultMailApp from Microsoft: https://docs.microsoft.com/en-us/outlook/troubleshoot/outlook-for-mac/useful-tools#setdefaultmailapp

Answer 3

If you don't want to install any third-party apps, one solution is to just add a junk mail account:

It will first try to connect for about a minute and fail. But afterwards you can click on "Sign in" again and it will close the accounts dialog, allowing you to change the Preferences.

Answer 4

You can use the system-installed Python interpreter to quickly change the default mail app.

Copy/paste the following command into Terminal, replacing com.microsoft.Outlook with the application bundle identifier for your mail app. Outlook's bundle identifier is com.microsoft.Outlook.

/usr/bin/python2.7 <<EOF
import LaunchServices;
result = LaunchServices.LSSetDefaultHandlerForURLScheme(
    "mailto",
    "com.microsoft.Outlook")
print("Result: %d (%s)" % (
    result,
    "Success" if result == 0 else "Error"))
EOF

If you're not sure what the bundle identifier is for your mail app, run osascript -e 'id of app "Some App Name"' to find it. For example, osascript -e 'id of app "Mail"' returns com.apple.mail.

Answer 5

SwiftDefaultApps seems to have superceded RCDefaultApp, which stopped working due to OSX changes, and the domain is down too.

brew install --cask swiftdefaultappsprefpane

Answer 6

The easiest solution is to use MSFT Mail Changer app for Mac.

You can download it from the page at this link.

https://docs.microsoft.com/en-us/outlook/troubleshoot/outlook-for-mac/useful-tools#setdefaultmailapp

Just download the .app file, no install, it gives you a list of registered mail clients, you pick one and done.

My company security (JAMF policy) blocks access to even open apple mail but didn't make this change so none of the share file commands from Word, Excel, or PPT would work. This app does the trick.

Answer 7

This answer works without any third party software. Solution tested on MacOS 12.6.1.

Place the code below in a Swift file. Replace the mailApp url with the path to your preferred mail application.

// DefaultMailSwitcher.swift
import Cocoa
let mailApp = URL(fileURLWithPath: "/Applications/Microsoft Outlook.app")
NSWorkspace.shared.setDefaultApplication(at: mailApp, toOpenURLsWithScheme: "mailto")

Then run from terminal with administrative privileges, without admin the command will silently fail even with a closure.

$ sudo swift DefaultMailSwitcher.swift

Confirm programmatically by running the code below from another swift file or clicking a "mailto" link.

print("After: ",NSWorkspace.shared.urlForApplication(toOpen: URL(string: "mailto:[email protected]")!))

Answer 8

Sometimes, even after setting Outlook as default mail client in Apple Mail - with an account you remove afterwards - (how could Apple ever think this is a good place to stick this setting) it does not stick.

Just to be sure, after setting the pref in Mail, run this through Terminal:

/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/\
  LaunchServices.framework/Versions/A/Support/lsregister -kill -r -all local,system,user

Answer 9

I know it's an old question, but I needed to do the same, possibly from command-line, and I found a solution.

You will need Homebrew, which can be installed with:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Then, you will need duti, which is available through Brew:

brew install duti

Now, we need to find out the name of the mail application you want to set as default, we can do that running the following command (change Airmail with your desired mail client):

mdls -name kMDItemCFBundleIdentifier -r /Applications/Airmail\ 3.app
# this will return "it.bloop.airmail2"

Now, we can set our desired app as default mail client with:

duti -s it.bloop.airmail2 mailto

That's it!

Answer 10

This was funky for me, but I had to modify a code block noted above. Steps I had to take to make this work (hoping it helps someone)

1. Open Terminal

2. Install launchservices newest module

3. Switch to Python (this is for 3+ due to launch services being I had to modify for CoreServices)

   import CoreServices;
   result = CoreServices.LSSetDefaultHandlerForURLScheme(
       "mailto",
       "com.microsoft.Outlook")
   print("Result: %d (%s)" % (
       result,
       "Success" if result == 0 else "Error"))
   EOF```
   
   

4. Reboot

5. Open Mail.app and use all my Exchange info (tried using a bogus email/comp but it still tries to auth even when you use an "other mail option")

6. In Preferences > General tab there's a default mail client, update to Outlook.
   (I tested mailto on the Mail app to ensure it registered. When it did I went ahead and swapped to Outlook)

7. Test mailto

Answer 11

Sometimes the easiest solutions stare us in the face and it's easy to overlook them. I get asked this regularly and the easiest way to do this is to just set up Apple Mail with your email account and then change the default email application to Outlook.

You don't have to use Apple Mail again after that. So, while you're technically still adding an account to Mail, you don't have to use it, or you can remove it after you've set the default to Outlook.

EDIT

I just wanted to add that in some cases, certain Apple software (e.g. Photos) have their own settings for which email client to use when sharing content. So you will need to select Outlook as the default within these Apps as well if you want to share content via email.