Windows Defender Alert Levels

When Windows Defender detects potentially malicious software, it assigns one of the following alert levels to it:

• Severe Assigned to potentially unwanted software that can severely affect your computer or compromise your privacy. You should always remove this software.
• High Similar to the severe rating, but slightly less damaging. You should always remove this software.
• Medium Assigned to potentially unwanted software that might compromise your privacy, affect your computer's performance, or display advertising. In some cases, software classified at a Medium alert level might have legitimate uses. Evaluate the software before allowing it to be installed.
• Low Assigned to potentially unwanted software that might collect information about you or your computer or change how your computer works but operates in agreement with licensing terms displayed when you installed the software. This software is typically benign, but it might be installed without the user's knowledge. For example, remote control software might be classified as a Low alert level because it could be used legitimately, or it might be used by an attacker to control a computer without the owner's knowledge.
• Not yet classified Programs that haven't yet been analyzed.