The update addresses a number of non-security issues, too. For example, it fixes a problem with when clicking a link on a web page that uses a custom pluggable protocol, such as notes:// or skype://.

It also fixes a problem users were having with Windows Live Mail and Windows Mail after installing IE9. (Users were finding that, after installing IE9, they were unable to in those mail applications.)

While past versions of Internet Explorer have been criticized for security holes, IE9 is considered to be on the market. A study in August, for example, found that the software offers Web surfers against social engineering malware.

NSS Labs researchers discovered that IE9 blocks malicious URLs over 99 percent of the time--compared with just 13.2 percent of the time for Google Chrome, 7.6 percent of the time for Firefox 4 and Safari 5, and 6.1 percent of the time for Opera 11.

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