In Photoshop CC (latest update), how do I change back to just "edit/transform" instead of "edit/transform path"? I have never had this happen before, and when I go to transform a layer, I get an error message "Could not transform the path because the selected portion of the path does not enclose any pixels." Help!
tl;dr: This is due to entering the quick mask mode. Press the 'Q' key and the problem should be gone!
Longer Explanation: At the bottom/end of the "tools" bar (see image below), there is a button for editing selections in "quick mask mode", i.e. selections are created using a brush. When this button is pressed, then attempting to transform a path seems to fail with the error message mentioned in the question.
The shortcut to this button is to press the 'Q' key on your keyboard. Thus it is easy to activate the quick mask mode by mistake and then wonder what happened.