UX audits

A UX audit is a review of an existing product to find usability problems. In the example, the error "Invalid input" is flagged as too vague, with its impact and a recommendation.
Audits often combine expert review against heuristics with existing data, such as analytics, support tickets and past research.
Each finding should state the issue, why it matters and what to do about it. An outside reviewer can bring a fresh perspective.