How To Create an HTML Signature in Mac Mail on OS X Mountain Lion

To make your business emails look more impressive you can add a full HTML signature in Mac Mail. You can add corporate logos, styled text, anchor tags and even graphical links to social media.

The process isn’t quite as straight forward as in Outlook for Mac or Thunderbird, but the below tutorial will show you how it’s done in Mac OS X Mountain Lion

  1. In Mac Mail, go to Mail -> Preferences -> Signatures and create a new signature by clicking the plus button (+). Add some temporary content inside, it will be replaced with your HTML later.
  2. How to create an HTML signature in Mac Mail Mountain Lion

  3. Create your HTML signature in a code editor like Adobe Dreamweaver, we have written a list of free and open source alternatives to Adobe Dreamweaver you can use to get started. The page should not have html,head or body tags, should include only inline css, and should only consist of basic html elements (div, span, img, a, etc…). Close Mac Mail.
  4. How to create an HTML signature in Mac Mail

  5. Ensure Mac Mail is closed. You will need to browse to a hidden folder on your Mac. Open a new Finder window and open the ‘Go’ menu at the top. Hold down the Alt/Option key and you will see the ‘Library’ option appear, click it.
  6. Open the Library holder on Mac OS Mountain Lion

  7. Once you have opened the Library folder, browser to the following location:
    Mobile Documents/com~apple~mail/Data/MailData/Signatures/
    Mail automatically created a ubiquitout_XXXXXXX.mailsignature file that represents it in this folder. Locate the correct .mailsignature file by sorting the folder by Date Modified. Open the newest file in your code editor.
  8. How to create an HTML signature in Mac Mail

  9. Once opened, you will see a few lines of metadata code on the start of the file. Keep the top metadata lines, but replace the below HTML in the file with your own code from step 2.
  10. Paste your code into the .mailsignature file

  11. Save and then close the file. When you next open Mac Mail the file will be wiped and be overwritten with your temporary text from before. To prevent this from happeneing you need to lock the file. Right click the file and click ‘Get Info’. Under ‘General’ check the ‘Locked’ box and then close the window.
  12. Click 'Locked'

  13. Re-open the Mac Mail app. Click Mail -> Preferences -> Signatures and you should see your new signature in the preview pane. Images will not load in the preview pane, but work when sending emails. Test the signature works correctly by composing a new email.
  14. How to make a graphical HTML signature in Mac Mail in OS X Mountain Lion