I assume this is because you’ve added your inboxes to Filter spam messages in other mailboxes. Indeed, this can make Mail slow depending on what kind of Mac you have and if there are ten thousand or more messages in the inbox. But I want to emphasize that setting up inbox filtering in this way is a workaround for a Mail bug. It’s not necessary for most users. Did you verify (e.g. using the green flags) that you were affected by this bug before applying the workaround?
I would be interested to hear more about why this is cumbersome. The recommendation is not to archive all read e-mails as you read them. It’s that, say, if you have 10 years worth of mail in the inbox, you could move the oldest 9 years to a different mailbox. It’s more something that you do once, or perhaps once every few months depending on how much mail you receive and whether we find another resolution for the bug, not a task that you would have to add to your daily routine.
Obviously, it’s your choice how you want to organize your mail, but the bottom line is that if you make this adjustment you’ll have fast SpamSieve filtering, much like before.
The timing is unfortunate. The plan had been to ship SpamSieve 3 as a paid upgrade this summer. The Mail extension would be available as an option for those who wanted a simpler setup and were not affected by the limitations of extensions. In this situation, you would have had the option of paying to get all the new features and improvements or staying with your old version.
When Apple made the surprise change in June, removing support for Mail plug-ins, that changed things. We had thought there would be another year of plug-ins because Apple had not addressed any of the significant plug-in limitations/issues that developers had been reporting since Monterey. Anyway, at that point we had to postpone the release of SpamSieve 3 to focus on getting the extra extension stuff working as well as possible before Sonoma’s release. So there is actually more in the upgrade than originally planned.
The bottom line is that there was going to be a paid upgrade before the switch to Mail extensions either way, and either way we’ll be working to keep improving the app and making those improvements available as free updates for a number of years.
I described in another thread the background of this situation, some possible avenues for speeding it up in the future, and how it may help to report this issue to Apple.
While I’m investigating ways to optimize the inbox scanning, there is another way you could set things up if you don’t want to move old messages out of your inbox. You can set up a Mail rule that filters incoming messages with SpamSieve via AppleScript. This will filter them immediately as they arrive, without having to scan the inbox. To set this up:
- Choose Settings… from the Mail menu and click the Rules button in the toolbar.
- Click the Add Rule button.
- Change the description to Move If SpamSieve Spam.
- Change the From pop-op menu to say Every Message.
- Change the Move Message pop-up menu to say Run AppleScript.
- Next to Run AppleScript, change the No Script Selected pop-up menu to say Move If SpamSieve Spam. (The script should be pre-installed if you had been using SpamSieve 2. It’s also available for download here.)
- Now click OK to close the rule and save your changes. Mail may ask if you want to apply the rule; click Don’t Apply.
- Make sure that the Training settings are set to use the the Junk mailbox.
Note that, unlike with the old plug-in based SpamSieve rule, with the script rule Mail will keep applying the rest of the rules even if the rule marks a message as spam. So it effectively acts last, and you may want to put it at the bottom of the rule list for efficiency and to make this clear. However, I doubt this would really be a problem in your situation because you wanted a way to filter messages that were left in the inbox, anyway.