Resolve Outlook 2007 and POP3 Performance Issues in Windows Vista

There are some functionality problems associated with the usage of Outlook 2007 on Windows Vista and POP3 accounts. Outlook 2007 users on Windows Vista have complained that the application becomes virtually unusable with POP3 accounts. The issue is limited to Outlook 2007; Outlook 2003 is not affected.

When it comes to downloading emails from POP3 accounts on Outlook 2007 in Windows Vista, users have reported extremely slow speeds. In fact, Outlook 2007 crawls, downloading no more than 1 MB of emails per hour. Microsoft has even published a Knowledge Base article addressing the slow download times between a POP3 server and Office outlook 2007.

According to the Redmond Company, the issue is closely connected to a new feature in Windows Vista, namely TCP Windows Scaling. In the scenario in which a network hardware device, a router for example, does not deliver support for TCP Windows Scaling the users are going to experience the slow download speeds mentioned above.

One easy workaround to this issue is to navigate to Start, All Programs, Accessories, and run Command Prompt with elevated privileges. Simply right click and select Run as Administrator. In the Command Prompt you will have to type in this command "netsh interface tcp set global autotuninglevel=disabled" and hit enter.

This command will set the value for the autoTuningLevel parameter as disable. The next time you fire up Outlook 2007 in Windows Vista you will find that the slow download speeds from a POP3 server are no longer an issue. Keeping the disabled value for the autoTuningLevel parameter can be a permanent solution. Alternatively, users can also identify the hardware that does not support TCP Window Scaling.