How To Create Your Own HTML Signature in OSX Yosemite’s Apple Mail

How To Create Your Own HTML Signature in OSX Yosemite’s Apple Mail

Unfortunately, creating high quality custom email signatures in Apple’s Mac Mail can be a pain, so we’ve created a nifty tutorial on how to embed HTML signatures in Apple Mail. If you’re on OSX Yosemite (10.10), here’s how it’s done:

1. Open Mail and go to Preferences > Signatures. Create a new signature and add any random content as a placeholder.

After creating your placeholder, make sure to close your Mail app.

2. Write your HTML code using your favorite editor. This markup should include only basic html tags like <div>, <span> and <td>. Don’t get too fancy since Mail only accepts inline css. In case you’re confused, I’ve included a code snippet of my email signature.


3. Now we need to locate the hidden files you need to edit the placeholder signature you created in Step 1. Normally, you cannot edit these files since Apple usually does not allow this. Using Finder won’t help too. However, the files are usually in three places.




4. Locate the Terminal app in Applications > Utilities and paste the appropriate line to your case.




It should look like this.

The code you’re adding tells Terminal to list files found in that directory, display relevant information and sort it by date. Press enter and find the filenames that start with ubiquitous_ and ends with .mailsignature. These are the files that we are going to edit. If you only have one ubiquitous_ file, this is most likely the placeholder signature you created earlier. But if you have multiple, check the date stamp on them and open that. However, since Terminal doesn’t allow you to double click on items, here’s how to do just that.




5. If that worked, you should now have opened a TextEdit file of your placeholder. If it didn’t, make sure you used the code appropriate to your case and pasted it in a single line. Also check if you have properly closed your Mail app.

Your TextEdit file should look like this. Select the placeholder text below the metadata information.


And replace it with the code you created in Step 2. Do not delete the metadata information.


After you’ve checked that everything is in order, save and close this file.


6. This step is ONLY for those who do not use iCloud Drive and iCloud.

Saving the file is not a guarantee that Apple Mail will use your new awesome signature. Mail could still override it by modifying your code. You need to lock the file by locating it on Finder and pressing + I to open the file information. Tick the Locked checkbox like so.


7. Once that’s done, open Mail and go to Preferences > Signatures. If you have included images in your signature, they will not show up on the preview pane. They will however show up on your real signature provided that the image source is a valid one.


8. To check if everything is working, try composing a new email message using the account that you’ve associated with the signature, and add your signature on the From box. Your new signature should now display properly.


Congratulations! You have succeeded.

However, if you’re unsure about your HTML signature design or have problems with its implementation, we offer this service on Drew Drew This at very reasonable rates. Just send us an email at

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1 Comment

  1. Here’s a tip! If you find yourself editing your signature files regularly, create a shortcut to the folder and put it in your Home folder or somewhere easily accessible.


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