Since updating to Anki 2.1.35 on MacOS the facility to detect duplicates when adding new cards appears not to work any more. When adding a new card with a ‘front’ field that I know already exists, the field does not glow red or alert me in any other way to the existence of a duplicate entry.
I tried downgrading to the previous version by selecting the “Downgrade and Quit” button, then installed the previous version. However, upon starting Anki after that I receive a dialog box saying that Anki 2.1.35 has been released, but I am unable to click any of the buttons:
For the duplicate check issue, make sure that the notes have actually the same note type.
From the manual:
When Anki checks for duplicates, it only compares other notes of the same type. Thus if you add a capital city called “Orange” using the capital city note type, you won’t see a duplicate message when it comes time to learn how to say “orange” in French.