Most free antivirus programs don't offer much besides basic malware protection, but Avast Free Antivirus is a half-step toward being a full-fledged security suite, with many features you'd normally be charged for. It has not only a password manager and a local-network security scanner, but gives you lots of configuration options. [UPDATE: Since this review was posted, Avast Free Antivirus has added a secure browser.]
Yet while it didn't sap much of our computer's performance, Avast Free Antivirus took a long time to scan, and its malware protection could be better.
Avast Free Antivirus matches new files with a continually updated database of malware signatures. Anything that slips through is subject to behavioral monitoring that looks for telltale signs of malicious activity. If new malware is found on your machine, you can opt to upload it to Avast's servers for further analysis.
Avast Free Antivirus screens out malicious email attachments and rogue Web pages — which some other free antivirus products don't do — and offers a dizzying range of customization options for each feature. However, it doesn't scan online repositories of files for threats. It offers full and quick system scans, the former of which can be scheduled.
The software uses its Smart Scan feature to look for dodgy browser add-ons, weak passwords, compatibility problems, outdated software, network threats and performance issues. You can't fix performance problems, however, without subscribing to the company's Cleanup product for $23.88 a year.
You can use Avast Free Antivirus to scan any single drive, folder or file by locating the item with Windows Explorer or File Explorer, then selecting and right-clicking the item. But Avast won't automatically scan a USB thumb drive when it's plugged in.
Avast Free Antivirus was better at catching malware than Microsoft's Windows Defender or Security Essentials, but paled next to the more effective malware shields of the other free Windows antivirus products we reviewed.
In Windows 10 evaluations conducted by the independent German lab AV-TEST, Avast Free Antivirus caught 98.8 percent of previously unseen, or "zero-day," malware in September 2015, and 96.7 percent in October. Yet AVG, Avira and Bitdefender each stopped 100 percent in each month.
Avast did better against widespread, previously recognized, malware, stopping 99.8 percent in September and 99.3 percent in October. But all the other free products we recently reviewed, aside from Microsoft's Windows Defender, caught either 99.9 or 100 percent.
In AV-TEST's Windows 8.1 evaluations, Avast Free Antivirus had more success against zero-day malware, stopping 100 percent in November 2015 and 98.3 percent in December. Against widespread malware, it was 99.8 percent effective in each month. That's not bad, but Avira and Bitdefender did better in both categories. Avast scored two false positives — benign software mistakenly flagged as malware — in November, and one in December.
On Windows 7, Avast Free Antivirus did acceptably well in AV-TEST's most recent round, stopping 98.2 percent of zero-day malware in January 2016, and 98.1 percent in February. Every other brand we recently reviewed did better, except Microsoft.
Against widespread malware, Microsoft Security Essentials — Windows Defender's older sibling — caught up to Avast. Both it and Avast stopped 99.7 percent in January, but in February, Microsoft edged ahead, with 99.6 percent to Avast's 99.3 percent. Avast scored three false positives over both months.
Avast's scores here are not bad. AV-TEST evaluates more than 20 antivirus brands at once, and Avast consistently ranks above average. It gets a solid B in malware protection, while the other four non-Microsoft products we reviewed in this round — Avira, AVG, Bitdefender and Panda — just happen to range from A- to A+.
In tests by a different lab, AV-Comparatives in Austria, Avast Free Antivirus stopped 99.4 percent of "real-world" (mostly Web-based) malware in November 2015, and 98.8 percent in December. That's not bad, but Avira, Bitdefender and Panda were a length ahead. Avast had one false positive in November and six in December, which sounds bad until you see Panda's total of 23, and Microsoft's total of 52.
Security and Privacy Features
Like most free antivirus products, Avast Free Antivirus has no sandbox to dry-run suspect software. But it does have a password manager, which you won't find in most free AV software, a secure Web browser for banking and shopping, and a game mode for interruption-free play.
The secure browser, called SafeZone, is based on Google's open-source Chromium browser, but we weren't able to add Chrome extensions. That's a good thing, as every extension is a security risk. We were able to take screenshots, however, which the competing free SafePay secure browser from Bitdefender won't let you do.
Avast Free Antivirus has everything you need to create an emergency rescue disk, except the USB thumb drive or blank DVD, that is. Most other free AV products make you download a program for this potentially PC-saving task.
Performance and System Impact
Avast Free Antivirus' impact on system performance was excellent, as long as you don't mind long scan times.
Without actively scanning, Avast let our OpenOffice benchmark test, which matches 20,000 names to an equal number of addresses on a spreadsheet, complete in 6 minutes and 56 seconds. That's just three seconds longer than the baseline time (set before any third-party AV software was installed) and indicates a passive system slowdown of only 0.7 percent.
Avast had a similarly light touch during active scans on our test system, an ASUS X555LA laptop running Windows 10 with 6 GB of RAM, an Intel Core i3-4005U processor and a 500GB hard drive holding 36GB of data.
During a full scan, the OpenOffice benchmark finished in 7:07, a lag of only 14 seconds, or 3.3 percent, from the baseline. That's better than all the other products we tested, whose full-scan system impacts ranged from 5.1 percent (Bitdefender Antivirus Free Edition) to 55 percent (AVG AntiVirus Free). In fact, it's not much heavier than AVG's passive impact of 2.7 percent.
Oddly, Avast's quick-scan benchmark time was 7:10, slightly more than its full scan result but still much faster than all the other products. Its system impact was 4.1 percent.
Minimal system impact often means maximal scan time, and Avast indeed had the longest scans among the free AV products we reviewed. Its full scan went through our laptop in an average of 1 hour and 24 minutes. (The upside is that it's so quiet, you might not notice any system slowdown.)
Most of the other products' full scans took about 45 minutes, although AVG had a lightning-fast time of just over 14 minutes. But most of the others mark 40 to 60 percent of files as inherently safe during their initial full scans, and ignore those files afterward. Avast Antivirus Free doesn't make any such assumptions and examines all the files each time.
Avast's user interface is bright, with lots of white, orange and green, although subsidiary windows can be darker. The main screen doesn't prominently display when the last scan took place, but that's under the surface. A prominent green check mark shows the system is protected; it turns to a red "X" or "!" when action is required.
Avast Free Antivirus has a Smart Scan button front and center on the main screen, but the meat of Avast's interface is in a row of top-level items: Scan, Tools, Passwords and Shop. Click on Scan to choose among probes for malware, browser add-ons, network threats and outdated software.
The Tools section is a bit of a tease because Avast's Sandbox and Firewall are upsell items, while the SecureLine virtual-private-network service is trialware. There are links to create Rescue Disk, to obtain Remote Assistance (more on this below) and to a very good statistics section.
Installation and Support
Avast Free Antivirus runs on Windows XP (with Service Pack 3) through Windows 10. Once you download the installer, you can either select the easy-installation route, or choose "Customize," which lets you pick which Avast Free Antivirus components to install. All told, it took 6 minutes to set up the software; other programs took a minute more or less.
Make sure you uncheck the two little boxes at the bottom left of the first installation screen. If you don't, the Google Toolbar will be installed on your Web browser, and its default search engine will be changed to Google. (If the installer comes from a third-party site, inspect every pre-checked option box.)
Avast notifies you that it may collect your personal information and Web history, but promises to strip identifying details and not to share or sell the information with third parties.
You don't need to register with Avast to use Avast Free Antivirus or receive malware-definition updates. Avast tries to upsell you to its paid products, but less intrusively than some other brands. The most annoying bit is a recurring notice at the bottom of the main screen that promises a "welcome gift." It's really an offer for a discount on the premium version.
Avast offers online technical support, and its technicians promise to respond within 24 hours of a query. You will need to register with Avast to do this, but some other free AV products only toss you into the discussion forums if you have a problem. You can also set up Remote Assistance from a more technically minded friend or family member — let's just call that "grandchild mode."
Avast Free Antivirus goes beyond what's expected of a free antivirus program by including a password manager and a home-network scanner. It has a barely noticeable system impact, and lets you make deep changes to how it operates. Yet the software can take a long time to fully scan a system, and doesn't offer the greatest malware protection. Still, Avast Free is good for those who want extra features with antivirus software, but don't want to pay for them.
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