Mozilla has blocked McAfee’s ScriptScan add-on for Firefox due to performance issues. This add-on was causing lots of crashes for the Firefox users, and Mozilla had to disable it to save users from possible crashes and slowdown.
McAfee’s ScriptScan is a part of its paid antivirus application, which get installed as browser plug-in for Firefox & IE, and scans web pages for possible malicious scripting codes. Hence it saves users from possible threats and scripting attacks. Unfortunately, this plug-in slows down Firefox and causes crashes. Mozilla describes this problem: “This add-on causes a high volume of crashes.”.
Users of McAfee ScriptScan v14.4.0 and below for all versions of Firefox and SeaMonkey have been affected by ScriptScan. Mozilla has suggested such users to disable this plug-in in order to avoid browser crash. McAfee’s another product, SiteAdvisor, has been blocked too for the same reasons.
In past, Mozilla had blocked various such add-ons causing browser crash and slowdown. Complete list of blocked add-ons can be checked here.