#8 McAfee

McAfee the security software firm apologized in September when the update to the antivirus software that generated false negatives for some malware on Windows personal computers, leaving users flummoxed.

"We would like to apologize for all the disruption caused to our many customers worldwide. We recognize the issue is very serious, and are doing everything we can to resolve it."

#7 Sophos antivirus

Security firm Sophos apologized in September for wreaking havoc on its customers' networks after a bad update to its antivirus software caused false positives for certain malware to occur on Windows machines.

Sophos apologized about the issue: "We would like to apologize for all the disruption caused to our many customers worldwide. We recognize the issue is very serious, and are doing everything we can to resolve it." Sophos said in its critical advisory, it thinks that the problem was caused by a release from SophosLab for use with its Live Protection system.