IT managers and users say that while the rash of security flaws associated with IE has drawn new attention to its vulnerabilities and has led some individuals to switch browsers, enterprises are reluctant to change browsers because of their reliance on IE-specific intranet applications and Web sites.
[...]"Most people here are just interested in doing their job," he said. "Unless someone is really inclined to have an additional layer of complication, they stick with IE."
[...]Downloading a new browser such as Firefox or Opera is often easier than following complicated configuration changes suggested by Microsoft and security researchers or downloading patches.
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Enterprises Slow to Dump IE"