How to create a 'New Email with Attachment' option in Finder?

Solution 1:

Is the service present and enabled in the Services section of Keyboard Preferences?

You should see this:

If it's not there for some reason, you can recreate it easily in Automator.

Create a new Service in Automator, add the "New Mail Message" action to the workflow, and change the first drop down at the top so it reads "Service receives selected files and folders in any application". It should look like this:

Then save it, and you should have it available in your services menu.

Solution 2:

To create attachments, you can drag files from Finder into an empty email message. But I agree that this is too much work.

To save some keystrokes, you can create attachments by dragging files from Finder directly to the Mail icon in the dock - doesn't matter if Mail is running or not.

NB. In most cases dragging files to an app icon in the dock will do something meaningful, depending on the file type and the app.