>I just had yet another instance of a Symantec/Norton antivirus product (in this case, Norton Internet Security) causing major problems with a client. She lives in Outlook 2007 on Vista:
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>- she lost the Reading (Preview) Pane completely
>- when we turned it back on, it was empty and would not display the currently selected message
>- all incoming and outgoing mail was stuck/hung
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>Multiple Outlook restarts, Office Diagnostics, and complete machine restarts had no effect. PST file size was "relatively" small, only 550MB.
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>Uninstalling NIS and running the Norton Removal Tool fixed all problems immediately.
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>So, as a reward for explicitly buying NIS and getting Best Buy to put it on her new computer a few months ago:
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>- she lost almost 4 hours of her time
>- she has to pay for 45 minutes of my time to figure out what the problem was
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>She's now using AVG Antivirus (the paid version at http://www.avg.com/home-and-office-security). The "Plus Firewall" version is not necessary on machines running XP SP2 or later, which already have an adequate firewall. I have a number of clients running this product, with excellent success.
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>For small office networks, I've had good success with the Trend Micro suites.
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>Symantec/Norton antivirus products continue to receive my maximum de-recommendation/condemnation. Fundamentally, you pay good money for a protection suite in order to make your life easier. Symantec's products fail miserably.
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>I haven't had any recent experience with McAfee, but a couple of years ago I set up some brand new Dell laptops with McAfee trialware preinstalled. Trying to uninstall that crapware BSODed all the machines; I later found out from Dell tech support that that product could only be uninstalled via a safe mode start. That's the angriest I can ever recall being about a piece of software, and at the time I swore I'd never consider McAfee again.

After a major computer meltdown in January, and based on advice here, I switched from Norton to AVG. I have been extremely happy with it. I also run Norton Ghost, Pop-Up Stopper, Ad-Aware, and two different backup programs, one local and one remote. Never again!