BitDefender Internet Security 2008 ($40 for one PC, $50 for three PCs) pairs shining success with disappointing failure. It outperformed every other suite in crucial malware detection tests, unmasked every rootkit sample, and finished second among the eight suites evaluated for our "All-in-One Security Suites: Tried and Tested" roundup on a separate spyware and adware detection test.

But this stellar performance behind the scenes was seriously marred by an unpleasant user experience. From aggravations with the initial installation to difficulties with warning pop-ups, BitDefender's flaws are hard to brush off.

BitDefender did extremely well when subjected to AV-Test.org's 674,589 inactive malware samples, detecting 98 percent of them. It also did the best job of detecting new, unknown malware in heuristics tests, with a 29 percent catch rate using one-month-old signatures. And it also tied for first with Kaspersky Internet Security 7.0 for the fastest response (0 to 2 hours) to malware outbreaks.

The suite detected all six inactive rootkit samples, though its efforts to disinfect one of them (Vanquish) crashed our test computer. BitDefender caught 97 percent of inactive spyware and adware samples, too, but it was our test group's second-worst offender at flagging false positives--though its 0.06 percent rate for false positives lies within an acceptable range.

As an infection remover, BitDefender didn't hold up as well. It successfully sanitized the files related to four out of five infections, but it completely failed to remove changes to the Windows Registry. Though they pose less danger of serious harm to your system than malware files, altered Registry entries can interfere with the smooth running of your PC.

BitDefender's firewall successfully masked a protected PC against outside scans, but it displayed needless warnings when the Firefox Web browser tried to access the Internet. That program should be on any firewall's list of known (and approved) applications.

The suite offers a good array of secondary features, including antiphishing, parental controls, antispam, and data privacy. But these extras need polish. The browser-based antiphishing tool didn't block any sites until I enabled the feature's heuristic detection, which is off by default. When I enabled parental control for other users, I wasn't prompted to set a program password--but if you fail to do so and you set up your kids' accounts with administrator rights, they'll be able to turn off the parental controls.

The antispam features currently tie into Outlook and Outlook Express only; a few other suites tie into Windows Mail and Thunderbird as well. The suite's Identity Control data privacy features requires that you manually enter any data (such as credit card numbers) that you want to prevent from being sent out on the Internet. Though that practice is fairly standard among suites, BitDefender pushes you to create the definitions on first use, and it's not easy to figure out how to bypass this step.

BitDefender's warning pop-ups did a poor job of guiding us through the steps of removing a detected e-mail worm (Warezov). The pop-up alert had options for ignoring, quarantining, or deleting the file. But perhaps because ther malware was lurking inside a .zip file, the security suite's default option was to ignore the infection. Choosing to quarantine the archive failed, but rather than alerting me to the failure. the program just popped up the same window without the quarantine option. Choosing delete finally worked.

Unlike every other suite we tested, BitDefender doesn't provide contextual help links that take you straight to the parental control help section if you click 'Help' while changing those settings, for example. Also, BitDefender asked again for the program registration code and registration information when we logged on as another user on the same PC. The company acknowledged that this is a program bug it intends to fix.

If BitDefender's interface and warnings were anywhere near as good as its virus detection engine, the suite would be easy to recommend. But its confusing pop-ups, program bugs, and high false positive rate make it best suited to a user who has strong technical skills and can at times make the right security choices without guidance from the software.

Erik Larkin