 In AV @-@ TEST 's 2011 annual review , Microsoft Security Essentials came last in protection , seventh in repair and fifth in usability . In the 2012 review , it came last in protection and best in usability ; however , having lost its certificate , it was not qualified for the usability award . In June 2013 , MSE achieved the lowest possible protection score , zero . In August 2015 for Windows 7 it was last , with 3 blobs out of 6 for protection . Performance — in the sense of speed — and usability were good . MSE found 99 @.@ 7 % of " widespread and prevalent malware discovered in the last 4 weeks " , slightly better than the industry average , but only 87 @.@ 2 % of " 0 @-@ day malware attacks , inclusive of web and e @-@ mail threats " , against an industry average of 98 @.@ 2 % . 
