Errors of omission in routine care can result in patient harm. This report discusses factors contributing to a pulmonary embolism in a recovering stroke patient exacerbated by a lack of intended but omitted venous thromboembolism or VTE preventative care. The system improvement recommendations drawn from the incident analysis include that the UK National Health Service develop a standardized approach to VTE risk assessment and broad-based training to enable a cross-section of clinicians to use VTE prevention devices as required.