How to Reset what the Spam Filter or a Label Has Learned

In the properties (right-click on view -> properties) of "All Messages/Spam" or a label under the "Labels" access point, there's a "Learn from labeled messages" option on the options tab. It's enabled by default for "All Messages/Spam".

What this does is add/remove/adjust internal rules for the label when you add or remove a message from the label. This causes the label to learn. But, you have to train it *a lot* so it doesn't have false positives. It can be really useful, but again, it takes a lot of work.

If you need clear what the label has learned, all you should have to do is uncheck "learn from labeled messages" for the label. Then, after you apply the change by closing out of the dialog, you can go back in and turn it back on if you still want it on.

The learned rules for each label are located in an ini file in the autofilter folder in the mail folder. If for some reason unchecking "learn from labeled messages" doesn't clear what the label has learned and the ini file for it in the autofilter folder isn't deleted, you can close down Opera and delete the ini file for the label. You just have to open each ini file and figure out which one is for the label in question.