Unable to copy highlighted text from Preview in MacOS

You do not have to remove the PDF annotation (e.g. highlight, underline) in order to copy the underlying text. You do have to deliberately select the text in the PDF that has received the annotation, as you would for any other text, that you wish to copy — provided that the PDF has no restrictions on copy.

Preview is not a PDF editor. When you add annotations (e.g. highlight, underline, etc.) in Preview, these are added as layers below, or above the PDF text, and the original PDF content remains unaltered. Because something is highlighted does not mean that it is preselected.

In High Sierra, you select and highlight some text. You reselect that text, and your options for copying are command+C, or Edit menu : Copy.

Some genius at Apple has removed the secondary menu Copy item when the text is both highlighted, and selected. If the text is only underlined as part of the annotation, then reselecting that text will show the Copy item on the secondary menu.

I copy a null string to the clipboard. I highlight and select some text. I copy that text to the clipboard.

Sequentially repeating the first three sentences, first with Edit menu → Copy, and then command+C — results in the same content pasted into hexdump (Terminal).

It is working for me on 10.13.2 Supplemental.

The shortcut does highlight the Edit menu, and the Edit->Copy also *seems* to work, but they don't. Trying to Paste just beeps, whereas Command-C on a selected and not highlighted text does work.