To download and install the KB915597 definition update, follow these steps:
You can still fetch it from: https://www.catalog.update.microsoft.com/Search.aspx?q=KB915597 — then filter by 1.155.11190.0 . To download and install the KB915597 definition update,
The update is the standard daily security intelligence (definition) update for Microsoft Defender Antivirus To download and install the KB915597 definition update,