When you have Gmail configured as POP3 account in you email client, the messages in the spam folder are never downloaded. So in order to make sure you’re not missing any important email, you need to log into your Gmail account with your Web browser and check the spam folder every week or so. Those who set up their Gmail accounts as IMAP accounts in their email programs won’t have to worry bout checking Gmail on the Web since folders in IMAP are synchronized between Gmail and the local email client – hence the Spam folder would show up in your email account along with all the other folders in Gmail.
Gmail, when it’s set up as a POP3 account in an email client, never downloads the emails in the spam folder — and there are no settings that allow you to download the mail from the spam folder. The only way you can check to see that there isn’t any important email in your spam folder by mistake, is to login to your account on the Web. If you find a “good” email, mistakenly labeled as spam, just mark it “Not spam” and it will be moved the mail to the Gmail Inbox. When it has been moved to your Gmail Inbox, it will be retrieved by your email client the next time you check mail.
Don’t ever assume because you’ve got Gmail set up as a POP3 in your email program, you’re downloading all your email. You’re never downloading anything from the spam folder. This is what makes using a Gmail account in your Email program a good way to fight spam – especially if you have Gmail gather your messages from your other accounts. But still, Gmail’s spam filtering isn’t perfect. No spam filtering is. We happen to think it’s the best spam filtering available right now. Gmail’s spam filtering is very good, but it is not perfect.
So if you’ve have your Gmail account set-up in your email program as a POP3 account, make sure you login to your Gmail account every week or so and go through your spam folder to make sure you’re not missing any important emails. If you don’t check your spam folder, Gmail will automatically delete its contents at intervals of its choosing and if there are any important emails in the spam folder, they’ll be gone with the spam. If your email client supports it, set up your Gmail account as a IMAP account and you won’t have to login to Gmail for anything – unless you want to change your Gmail settings.