An integrated threat protection solution designed to detect, investigate, and respond to cyber threats across Microsoft 365 services.
Hi, Bonnie Alder
Microsoft Defender is separate from Excel, so Office working does not confirm that Defender can be downloaded. Also, Windows already includes Microsoft Defender Antivirus through Windows Security, while the separate Microsoft Defender app is included with Microsoft 365 Personal or Family.
Here are some suggestions you can try:
Open Start, search for Windows Security, then open Virus & threat protection. If protection is active, the built-in antivirus is already working and does not need to be downloaded.
If you want the separate Defender app, confirm that you have an active Microsoft 365 Personal or Family subscription, then install it from the official Defender installation page. Sign in using the same personal Microsoft account connected to the subscription.
If Microsoft Store shows “Unable to download,” press Windows key + R, enter wsreset.exe, and select OK. After the Store reopens, sign out, sign back in, and retry.
Install pending updates under Settings > Windows Update, restart the computer, then update Microsoft Store from Library > Get updates.
If it still fails, please share the exact error code or a screenshot.
Thank you for your patience in reading, I hope this information has been helpful to you.
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