NOTE: On December 6, 2016, an incorrect detection for our cloud-based protection for Trojan:Win32/Detplock was identified and immediately fixed. To ensure that this issue is remediated, you can do a forced daily update to download your Microsoft antimalware and antispyware software. For details, see Updating your Microsoft antimalware and antispyware software.
What to do now
You might need to manually update your Microsoft security software: