I’m seeing this error in the log for several accounts: Skipping filtering inbox of account “[email address]” because it contains too many messages: 15676
If the messages are being filtered properly, you can ignore that error. Otherwise, this means that you are encountering an Apple Mail bug. SpamSieve has a workaround for the bug, but it’s currently limited to mailboxes with 5,000 or fewer messages. You can move messages to get under the limit or try raising the limit. A forthcoming version of SpamSieve will remove the limit entirely. There’s more information about this here.
Thanks for the quick reply. I keep training as spam, but for the most part nothing is getting moved to the Junk folder unless I repeat “training as spam” on each spam message. My most important inboxes have 15,000 to 20,000 messages in each one, so the workaround is no solution for me. I didn’t see any info on the page you sent the link to (https://c-command.com/spamsieve/help/why-do-good-messages-mo) about changing the limit of 5,000 messages.
Sorry, I gave you the wrong link. The correct one is this.
With SpamSieve 3.0.2b1 there is no more limit.