SpamSieve free download for Mac


20 August 2019

Robust spam filter for major email clients.


SpamSieve is a robust spam filter for major email clients that uses powerful Bayesian spam filtering.

SpamSieve understands what your spam looks like in order to block it all, but also learns what your legitimate messages look like to avoid confusion. SpamSieve only marks spam in your email client so you never lose any mail.

The following is a partial list of SpamSieve’s features, so that you can quickly see what it can do and how it’s unique:

  • Powerful Bayesian spam filtering results in high accuracy and almost no false positives. It adapts to the mail that you receive to get even better with time. Some other e-mail programs include Bayesian filters, but SpamSieve is more accurate.
  • Integrates with your e-mail program for a superior user experience. Plus, you get the same great filtering if you ever switch e-mail programs or use more than one at a time.
  • SpamSieve works with any mail provider/host. It filters all your mail accounts. There is no extra charge for additional addresses or devices.
  • SpamSieve running on your Mac can keep the spam off your iPhone/iPad, and you can even train SpamSieve from afar.
  • Colors show how spammy each message is, so you can quickly focus on the borderline ones if you want to check SpamSieve’s work.
  • Integrates with the macOS Contacts app (and also Eudora’s and Entourage’s address books) so that messages from friends and colleagues are never marked as spam.
  • Automatically maintains a blocklist so that it can instantly adapt to spam messages sent from particular addresses, and catch 100% of them.
  • Automatically maintains a whitelist to guarantee that messages from particular senders or mailing lists are never marked as spam, without cluttering your address book with these addresses.
  • You can customize the whitelist and blocklist, adding sophisticated rules that match various message headers, or the message body. The rules can match text in a variety of ways, including using regular expressions.
  • Can use the Habeas Safelist, which indicates messages that are not spam, as well as the "ADV" subject tag indicating that a message is spam.
  • Many spammers encode the contents of their messages so that filters cannot see the incriminating words they contain. SpamSieve can decode and look inside these messages. Optionally it can mark them all as spam, on the theory that legitimate senders do not try to obscure their messages.
  • SpamSieve keeps track of how accurate it is, how many good and spam messages you receive, and how these numbers change over time.
  • Turn off new-mail notification in your e-mail program, and let SpamSieve notify you only when you receive non-spam messages.
  • The corpus window and log let you see how each spam message was caught.
  • Unlike server-based spam filtering services, your mail data stays on your own Mac, so your privacy is preserved.
  • SpamSieve supports AppleScript, so you can connect it to additional apps and fully integrate it into a custom workflow.

What's new in SpamSieve

Version 2.9.37:
  • SpamSieve is now compatible with Apple Mail under macOS 10.15 (which is now in beta).
  • It’s best to update to SpamSieve 2.9.37 now, before updating to macOS 10.15. If you are already using macOS 10.15, the SpamSieve 2.9.36 auto-updater won’t work, so you should instead use the Download button in the Software Update… window and install the update manually, according to the instructions in the Read Me file. Once you have SpamSieve 2.9.37, auto-updates on macOS 10.15 will work normally.
  • Updated the documentation for macOS 10.15.
  • The Outlook - Filter Mailboxes app is now notarized for compatibility with macOS 10.15. If you’ve already installed the helper app, it should not be necessary to update it, but this change is needed for future updates as well as new installations.
  • Various Apple Mail error messages and documentation are better at reminding you to grant SpamSieve Full Disk Access when not having that might be the cause of the error, e.g. SpamSieve thinking its plug-in is not loaded.
  • Apple Mail on macOS 10.15 has a bug where it will not load plug-ins that are installed in the normal location if you’ve redirected your home folder to another volume. If SpamSieve detects this situation, it will apply a workaround (moving the plug-in to an alternate location) and show an alert that explains what it’s doing.
  • Renamed the “Setting Up Outlook 365” section of the manual to Setting Up Outlook, as it covers all current versions of Outlook, not just 365. This section has also been substantially rewritten to make it clearer what to do for each type of account.
  • The Can other Apple Mail plug-ins cause problems with SpamSieve? section of the manual now recommends using Mail’s own plug-in manager instead of manipulating the Bundles folder directly.
  • Fixed a bug where SpamSieve would sometimes ask you to enable an old Apple Mail plug-in (which wasn’t possible, because it was old) and quit, where instead it should have offered to update it first.
  • Worked around an Apple Mail bug where training a message as good sometimes didn’t move it to the inbox because Mail reported a script error when checking whether the account was enabled.
  • Improved the diagnostic report.
  • Software Update… reports a better error message if it was unable to install the new version of the app.

170 SpamSieve Reviews

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17 December 2013

Most helpful

Although it is expensive, SpamSieve is a terrific, useful application. I would buy it again.
Like (8)
Version 2.9.12
08 September 2019
Hate Spam? Distrust your servers decision as to what is spam? This app is your best alternative! Hugely accurate. Learns quicker than you do. Support excellent. Yes it works just great in Catalina!
Version 2.9.37
19 August 2019
Apple mail without spamsieve is like being married with no wife.
Like (1)
Version 2.9.37
19 August 2019
Great software, always up to date quickly for new MacOs Outstanding support
Like (1)
Version 2.9.37
13 August 2019
Changed my life. Suddenly no more SPAM mails (>80 per day). Email is usable again. Amazing that there was no solution from Apple!
Like (1)
Version 2.9.36
09 June 2019
After linking to an insecure network overseas, I was getting a hundred or more spam messages every day, many of them offensive. With SpamsSieve, they're gone. You do need to follow the installation instructions precisely. And... do take the time to train the software to recognize your particular flow of spam. (It's all there is intro well-written but lengthy step-by-step instructions.) It's also important to monitor the Spam folder every day for the first couple of weeks or so to catch false positives and train SpanSieve to not delete a few specific email senders. (using version 2.9.36 - June 2019) You may need to switch your iPhone/iPad email from "Push" to "Fetch every 15 minutes" for new mail. That way, your Mac will discard the spam before it gets to your mobile device. The downside is that there can be as much as a 15-minute delay on your mobile device unless you go to settings and fetch manually when you're expecting an urgent email.
Like (1)
Version 2.9.36
22 March 2019
After training and having used for a few months now, it is currently almost faultless. Currently no false positives (identifying good email as spam), barely any false negatives - way, way better than Gmail or Ourlook. Because (by design) it runs locally on your main device, control and security are maximised, but it means it's a bit fiddly to set up and other devices may pick up spam if the main device hasn't processed the emails on the IMAP server. For that reason, would love a cloud-based version.
Like (1)
Version 2.9.35
20 December 2018
How could we live without it? ;-)
Like (1)
Version 2.9.35
20 December 2018
Excellent software works perfectly support is incredibly fast and accurate
Like (2)
Version 2.9.34
08 October 2018
If you have a spam problem and most of us do SpamSieve will solve your problem. Takes a bit of time to train but the time and minimal effort is well worth it. I use it in Apple Mail and Airmail 3 and it performs very well. My spam stopped happening. Works just fine in Mojave.
Like (2)
Version 2.9.33
07 September 2018
SpamSieve has been painful for me so far. First it wholesale moves a large number of "good" emails into Junk just as I was beginning the process of "training" it. Now I have to find them and move them back, because marking them as Good (in Junk) only moves the marked one back to Inbox. Also, about once a minute it locks up Outlook for a few seconds (shooting to 78%+ of the processor usage), making Outlook nearly unusable. Am I missing something?
Like (2)
Version 2.9.32
1 answer(s)
C-Command Software
C-Command Software
13 September 2018
I’m sorry to hear that you had good messages go to the Junk mailbox. With Outlook 365 (unlike other mail clients), SpamSieve will filter unread messages that arrived in the inbox before you started using SpamSieve. Normally, this isn’t an issue because the instructions have you do the initial training before you finish activating SpamSieve. But if you don't train very many messages, it could incorrectly catch some of your old good ones.

I'm afraid I don't understand your point about only moving the marked one back to the inbox after training them as good. SpamSieve does not filter messages in other mailboxes, so where else would you expect the messages to move back to?

Yes, you are missing that if you have lots of messages in your inbox you should be using this setup:

This works around a performance issue with Outlook and large inboxes by creating a separate inbox folder for the messages that you want SpamSieve to filter. (And it also avoids the problem of processing old unread messages that are in the inbox.)

If you have further questions about setting up SpamSieve with Outlook, please contact
Like (3)


App requirements: 
  • Intel 64
  • Mac OS X 10.7.0 or later
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