An updated version of Windows Defender Beta 2 is now available from the Microsoft Download Center. This update resolves the two issues described in the below blog post relating to non-English versions of Windows and referenced in KB915087. If you are running on a non-English version of Windows, then we advise that you uninstall the previous installation and install the updated version. If you are running on an English version of Windows, then no action is required.
Also, a new definition update package is now available from Microsoft Update which should resolve the problem described in KB915105. Users with Automatic Updates enabled will be notified of the availability of the release in a manner consistent with their Automatic Updates settings.