Spam Filters for Your Mac: Six Choices

Published on: April 19, 2007
Last Updated: April 19, 2007

Spam Filters for Your Mac: Six Choices

Published on: April 19, 2007
Last Updated: April 19, 2007

Joe KissellJudging by the marketing campaigns of leading ISPs and email providers, that whole spam problem is history.

Advanced defense mechanisms built into modern mail servers have supposedly made junk mail a thing of the past.

What little spam the servers might not catch, your desktop email client should; most such programs on the Mac, including Apple Mail and Microsoft Entourage, have built-in junk mail filters that promise to keep your Inbox spic and span.

But somehow, despite the promises, most of us still get boatloads of spam every day.

Maybe the server-based filtering isn’t as robust as it could be, or maybe your client’s internal filter can’t keep up with spammers’ latest tricks.

Whatever the case, many Mac users find that they need more powerful tools to rid themselves of the scourge of junk mail.

Luckily, help is at hand. Numerous add-on programs use any of several advanced strategies to weed out unwanted messages while ensuring that legitimate email makes it through correctly.

Of course, each product comes with an equally grandiose claim of superiority, but they’re not all created equal.

If you’re looking to beef up your last line of defense against spam, you should carefully consider the effectiveness and ease of use of each candidate.


Because most of these programs employ Bayesian filters that learn from both good and bad email to become more accurate over time, their accuracy will vary from person to person according to what you feed them.

And, because spammers adjust their tactics to continually outsmart filters, results may differ from day to day too.

But in general, I’ve found that filters’ effectiveness increase as they bring a greater number of techniques to bear on spam.

Bayesian filtering is one good method; using regular expressions to match suspicious patterns is another; checking senders’ IP addresses against whitelists (of allowed senders) and blacklists (of known spammers) is still another.

Some filters go further still by checking for forged MX (mail exchanger) records or looking for spam encoded as HTML entities, images, or other attachments (which may include viruses, Trojan horses, and other malware).

The smartest spam filters use a combination of several techniques, assigning a weight to each test, so that a single suspicious feature won’t condemn a message, while a single benign feature won’t spare it.

Ease Of Use

My ideal spam filter would function invisibly in the background, zapping spam without making me leave my regular email client, cluttering my screen with new windows, or intruding into my work in any other way.

Of course, even the best spam filter can make a mistake, so you need to correct false positives and false negatives.

That capability can be handled by a pair of menu commands or keyboard shortcuts accessible in my email client, but some tools make corrections more cumbersome.

Each person’s situation differs, so it helps to be able to fine-tune a spam filter’s settings.

Should it be more aggressive or more forgiving? Can I add my own custom rule for some unusual type of spam I get frequently?

Can I specify what actions are taken when suspected junk mail is identified (such as deleting it, moving it to a Junk mailbox, or even sending a complaint to the sender’s ISP)? All things being equal, a simpler and cleaner interface for such tasks is best.

With those thoughts in mind, here’s an overview of currently available Mac spam filtering software.

I’ve included only those apps that have been updated since the release of Tiger (April 29, 2005) and that work with Apple Mail (though most of these also support other popular email clients).

1) Em@ilCRX

Price: $30

Works with: All email clients

Pros: Blacklist, whitelist, regular expression matching; image spam filtering; several other filtering options.

Cons: No Bayesian filter; no IMAP support; no direct integration with email clients; cluttered interface; poor documentation.

Em@ilCRX has a peculiar interface (with, for example, unlabeled checkboxes in odd places and a seemingly endless proliferation of windows).

It works only with POP accounts, and functions as a proxy: it checks your email, and then your email client connects to Em@ilCRX, from where it downloads the filtered messages.

You must always have Em@ilCRX running in the background in order to check your mail, and you must also switch to it to correct any false positives or false negatives.

Unfortunately, the setup process for both Em@ilCRX and your email client is odd, complex, and poorly documented.

If you can get past the setup and UI, the program’s functionality is comparatively solid, and includes options to record spam and phishing attempts in a central database and to report spammers to their ISPs (though I think the latter is less useful than commonly believed).

2) JunkMatcher

Price: Free (donations accepted)

Works with: Apple Mail

Pros: Bayesian filter; regular expressions; wide variety of actions available for suspected spam.

Cons: Complex UI; no universal binary version; nearly two years since last update.

In my testing, JunkMatcher has been extremely effective. The addition of keyboard shortcuts would be welcome, but otherwise it integrates well with Mail.

Although less-sophisticated users may be put off by the range of tweakable options, if you’re a geek who likes to tinker, you’ll love the fact that you can mess with JunkMatcher’s settings to your heart’s content.

(For that matter, it’s open-source, so you can alter anything you want if you’re so inclined.)

My one big concern: JunkMatcher hasn’t been updated in almost two years, and there’s still no universal binary (though it runs fine under Rosetta on Intel-based Macs). But since it’s free, you have little to lose.

3) Personal Antispam X4

Price: $50

Works with: Apple Mail, Entourage

Pros: Bayesian filter; blacklist; whitelist; attachment checking; integrates well with Mail and Entourage.

Cons: Adds lots of extra stuff (of questionable value) to your system; expensive.

Intego’s Personal Antispam X4 is, I’m sorry to say, a pretty good spam filter. Sorry? Well, here’s the thing.

It has a solid set of spam-prevention features, including a Bayesian filter, blacklist, whitelist, attachment checking, and more; it offers the cleanest and most seamless integration with Mail and Entourage of any spam filter available; and it even has a pretty user interface.

But, like all Intego products, it insinuates itself rather deeply into Mac OS X, installing a startup item that requires a restart, a new pane in System Preferences, and a couple of background processes that run all the time.

I find all of that (not to mention some questionable marketing practices on Intego’s part) rather icky, and I’d like to be able to tell you that the software itself sucks too.

But it doesn’t. On the other hand, it is pricey and doesn’t support many common email clients, so you still have at least two good reasons not to buy it.

4) Spamfire

Price: $40 (includes one-year subscription to filter updates; renewal costs range from $10 for one year to $35 for a permanent subscription).

Works with: Apple Mail, Entourage, Eudora, Mailsmith, Mozilla, PowerMail (automatic setup); most other clients (manual setup).

Pros: Automated setup for most clients works well; good configuration options.

Cons: Weak IMAP support; poor integration with email clients; ongoing subscription cost is a drag.

Spamfire is reasonably accurate, has a respectable range of configuration options, and has been acceptably stable in my testing.

But despite dramatic improvements since its initial release, it’s still clumsy to use. For POP accounts, it functions as a proxy that stands between your client and mail server (as does Em@ilCRX), which works fairly well.

But for IMAP accounts it checks your mail independently, which means you end up downloading most messages twice, and your email client might fetch some spam before Spamfire gets to it.

In either case, because Spamfire is poorly integrated with email clients, fixing mistakes is harder than it should be.

The program can optionally report spam to several different authorities, though as I mentioned in connection with Em@ilCRX, I’m not convinced of the usefulness of such tactics (so I consider that neither a pro nor a con).

For the price, you can get SpamSieve and a sandwich, a much better deal in my opinion.

5) SpamSieve

Price: $30

Works with: Apple Mail, Entourage, Eudora, GyazMail, Mailsmith, PowerMail, Thunderbird.

Pros: Bayesian filter with adjustable sensitivity; blacklist; whitelist; regular expressions; excellent integration with email clients; nearly invisible operation.

Cons: Limited actions available for suspected spam; some initial manual training required.

It’s hard to find anything bad to say about SpamSieve, the gold standard of Mac anti-spam programs. It’s highly accurate, unobtrusive, configurable, and frequently updated.

Of course, there’s still room for improvement. I keep wishing I could get SpamSieve to give me more granular control over how it treats suspected spam.

For example, I’d like truly obvious spam to be trashed immediately, and I’d like spam from different accounts to be routed to different junk mailboxes.

I wish the initial step of training it with spam and “ham” were more automated.

And I’d prefer that, like Personal Antispam X4, it were completely invisible when running in the background. But these are nits; it’s far and away my favorite spam filter.

6) SpamSweep

Price: $25

Works with: Apple Mail, Eudora, GyazMail, Mailsmith, Entourage, PowerMail, Thunderbird.

Pros: Bayesian filter; whitelist; domain and relay blacklists.

Cons: No IMAP support; limited configuration options; awkward procedure for handling false positives; sketchy documentation.

SpamSweep is essentially a minimalist POP client that also has some built-in spam filtering; you can, if you wish, read all your mail without leaving the program.

If you want to file it or reply to a message, though, you’ll have to ask SpamSweep to redirect it back to your POP account and then fetch it with your regular client, a somewhat cumbersome procedure.

(SpamSweep can launch your client automatically when good mail is detected, but that’s the extent of its integration.)

It includes only the skimpiest documentation (a brief Read Me file) and no control over how it determines which messages are spam (other than training it with good and bad messages).

My Recommendations

If ease of use is your primary consideration, Personal Antispam X4 comes the closest to the kind of transparency I find ideal.

But SpamSieve has superior accuracy, more configurable options, wider client support, and, if I may be frank, a much higher ranking on the warm fuzzies scale.

It’s also cheaper and only a teensy bit less pretty. So in all, SpamSieve is my top choice. If even $30 is too much to spend, JunkMatcher is also an excellent option, but bear in mind that its future is less certain.

None of my top recommendations takes the step of reporting spammers to the authorities, and although I think that’s of dubious value myself, you may feel it’s important.

If you do, look at Em@ilCRX or Spamfire; of the two, Spamfire has at least some support for IMAP and a cleaner interface, while Em@ilCRX has a wider range of filtering options and a lower price.

It’s difficult for me to recommend SpamSweep for anyone. It’s not terrible, but it’s just too limited. Because there are much better options in the same price range, there’s no compelling reason to choose SpamSweep.

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Written by Bobby

Bobby Lawson is a seasoned technology writer with over a decade of experience in the industry. He has written extensively on topics such as cybersecurity, cloud computing, and data analytics. His articles have been featured in several prominent publications, and he is known for his ability to distill complex technical concepts into easily digestible content.