Avast Free Mac Security Review: Our Top Free Pick

Avast offers top-tier protection and scans email for free, but it can slow system performance.

Our Verdict

Avast Free Mac Security's malware-squashing proficiency, negligible performance impact and included password manager make it the best free option.


  • Free
  • Excellent malware protection
  • Nearly no system impact in background
  • Password manager included


  • Packs bloatware

If you're looking for a free option, Avast Free Mac Security is the best antivirus for Mac you should be looking at, and it even throws in email scanning. Unfortunately, this software doesn't offer any other perks that you can't find elsewhere for free.   

Costs and What's Covered

Avast Free Mac Security is free. It supports Macs running any version of OS X, as long as they have 128MB of RAM and 750MB of available disk space.

MORE: Best Mac Antivirus Software

Antivirus Protection

Avast Free Mac Security keeps Macs free of malware using traditional signature-based detection and by unpacking Mac-specific formats and scanning them for malicious contents. It also detects and quarantines PC malware on Macs, to prevent it from spreading.

Not only does Avast monitor your computer and its network connections in the background, but it also allows for both on-demand and scheduled scans. Avast additionally scans your router to look for signs of malicious DNS hijacking and executable shellcode scripts. The program also scans unopened archive files such as ZIPs.

Antivirus Performance

Avast Free Mac Security's on-demand malware-scanning engine does a very good job of keeping a Mac infection-free. The engine stopped 99.17 percent of Mac OS X malware in German independent lab AV-TEST's most recent evaluations, conducted in June 2016. That's just below Bitdefender Antivirus for Mac's perfect, 100 percent score.

Avast tied with Kaspersky Internet Security for Mac, Sophos Home for Mac and Norton Security, which also all scored 99.17 percent, and did better than Avira Free Antivirus for Mac, which stopped 93.33 percent.

MORE: Best Antivirus Protection for PC, Mac and Android

Security and Privacy Features

Avast includes its Online Security browser extension, which automatically installs itself in Chrome unless you opt out, while Firefox provides a confirmation prompt to make sure you approve. The Avast extension appears as a button that is green when you're safe and red if a site is potentially harmful. Similar flags will appear next to search results.

If you're wary of sites that monitor your actions, Avast also displays a counter badge that tallies the number of activity trackers found in a website, and provides an additional option to block social network-based tracking.

Not only does Avast scan activity on your hard drive and web browsers, but it also monitors POP3 and IMAP email clients, including Apple Mail, Thunderbird, Postbox and Airmail.

Not only does Avast monitor your computer and its network connections in the background, but it also allows for both on-demand and scheduled scans.

However, Avast Free Mac Security doesn't have any of the extra features offered by paid competitors, such as firewalls or webcam blockers.

Performance and System Impact

Avast Free Mac Security had a moderate impact on system performance, which we assessed by running our custom OpenOffice benchmark test that matches 20,000 names and addresses on a spreadsheet. Our test machine was a Late 2013 MacBook Pro with Retina Display with a 2.6-GHz Intel Core i7 CPU, 8GB RAM and 23GB of data stored on a 512GB SSD.

With Avast Free Mac Security installed on our MacBook, but without any active scans running, the OpenOffice test finished in an average of 2 minutes and 23 seconds, one second longer than without any antivirus software installed. That's a passive system hit of 0.7 percent, not something you could likely perceive. Other antivirus products' passive system impacts ranged from 1.41 percent to zero percent.

In AV-Comparatives' tests, Avast detected 99.9 percent of malware.

You would be more likely to notice the slowdowns created by Avast's active scans. During full-system scans, the OpenOffice test finished in an average of 2 minutes and 37 seconds, a performance dip of 10.6 percent. That's not bad, although it wasn't as good as Kaspersky's 6.34-percent full-scan system hit. The worst performer in this test was Norton Security, which had a 28.17 percent system impact, something you would probably notice.

Avast's full-scan completion time was 17 minutes and 15 seconds, near the middle of the pack. By contrast, Bitdefender took only 31 seconds, winning the speed prize, while Sophos lagged behind, at 2 hours and 25 minutes.

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Avast's moderate system impact may be due to the fact that this program scans every file every time, unlike Bitdefender, which skipped unchanged files it had previously reviewed. The full-system scans of Kaspersky (which also scans every file every time) and Sophos took even longer to complete, but those longer times may have allowed the software to reduce system impacts.


Unlike other free antivirus software, Avast Free Mac Security provides a data-rich interface that gives users plenty of data and options. Its main window shows users a Protected status, as scans are enabled by default.

Avast's main window presents users with their status — Protected or otherwise — and a New Scan button. Clicking on New Scan presents a Start button for activating a Quick Scan and a Change Scan Type button to switch to a full-computer scan.

In the Scan tab, you can command Avast to search your whole system, mounted drives or discs, specific folders, or connected network devices. Avast representatives told us there is no scheduled scan option because the company believes you need only an initial hard-drive scan followed by background scanning.

You'll find database updates and analyses of scans performed on your system in Avast's Reports. Avast places files it flags as malicious into the Virus Chest quarantine section, where you can delete or restore them (if you think Avast is mistaken). Open the Shields section to see real-time analysis of scanned files.

In the Preferences tab, you'll find options to change the frequency of notifications, system updates and scans. Here, you can also disable hard-drive, email and web protection, though Avast makes you enter your system password first. Additionally, you can disable Avast's menu bar icon from this window.

Avast Free Mac Security had a passive system hit of just 0.5 percent on our MacBook, which is the second lowest rate we found.

If you create an account with Avast, you can check the status of any systems you've logged into in the Account tab, as well as at my.avast.com. Avast's menu bar button provides links to open the main interface window, see current activity and application information, and review previous notifications.

Installation and Support

To install Avast Free Mac Security, you open Avast.com and click Download. You'll be sent to Download.com, where you click the big, green Download Now button, which will place the installer DMG on your Mac. After you click through the end-user-license agreements, the installer will download more files and install Avast.

No restart is required, and the whole process took about two minutes for me, slightly less time than with some competitors. During that process, you'll be prompted to opt out of installing the Avast Online Security browser extension and the company's SecureLine VPN client. (You should also check to make sure no other software is set to be installed.) Avast Online Security is free, but you get only a seven-day trial of SecureLine VPN, which you can activate from a menu bar icon.

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To get technical support, click Help in the menu bar, select Avast Technical Support and select Contact Help to open Avast's Support site. Here, you can find a FAQ, ask for help in the forums and call a customer support line that will provide free support for installing, configuring, updating and removing Avast. If you need more help than that, Avast offers paid support that starts at $119.99 for one-off support calls, as well as yearly support plans for one year at $179.99 and for two years at $299.99.

Bottom Line

Avast's email scanning is a welcome bonus, and its malware-catching abilities are very good. But a lack of other security features and a noticeable dip in performance during a full scan makes it hard to recommend Avast Free Mac Security over the easier-to-use free Sophos or the more capable paid Bitdefender.