I was missing some emails that I should have been getting, so I wanted to find out what the heck was going on. I use Thunderbird and download my Gmail account email via POP3. I had the missing email problem before and the solution was to check the spam folder online at Mail.Google.com. So I did that, and low and behold, the emails were there. But these were emails that were important in terms of receipt in a timely manner, so I was not too happy about it. I wanted to find a way to download also the Gmail SPAM folder via POP3 to Thunderbird. In Yahoo Mail I can easily do this with the tick of a checkbox, but looking all over the Gmail settings I couldn't find anything. I looked around online and it seemed this is only possible if you use IMAP with Gmail. I don't want to use IMAP in this case because I'm using the global inbox in Thunderbird, and I don't want to manually click on the spam folder here and there to check. I might as well go to Gmail on the web to do that.
Then I found this tip by Aaron Kelly on how to disable the Gmail SPAM filter
. Works perfectly. I've added a pair of screen shots below to help you accomplish this. Basically all emails will be told to "Never send it to Spam". I'm happy with the spam filtering in Thunderbird, which I have more control over and have trained to my liking.
Step 1: Setting up the filter condition (from = *)
Step 2: Setting up the filter action