Why are some emails missing when I apply a label filter?

Gmail’s labels system is quirky. When you apply an a label to a conversation (ie, a thread), it only applies the label to all the emails that exist in that thread at that moment. It does not apply the label to any future emails that are received or sent within that thread.

This is counter-intuitive because most of us use Gmail’s “conversation view,” which groups emails in a thread together, making each email look as though it’s properly tagged with the label.

But it’s an illusion — they aren’t! You can verify this by looking at the emails individually, non-grouped, by turning off conversation view in your Gmail settings. This will show each individual email and the labels it has applied to it. You’ll see that any emails in the thread that were sent or received after the label was applied to the conversation will not have the label applied to them.

So what’s the fix?

You have 3 options:

1. Re-apply the label to the conversation after every new email is sent or received in the thread.
2. Wait to apply the label to the conversation until it’s been closed or completed.
3. Apply an automatic Gmail filter rule that automatically applies labels to emails that meet specific conditions.

None of these options is ideal, I know. Why doesn’t Google just automatically add the label to every subsequent email in a conversation? They knowingly admit to not doing this, as shown in this support article.

If conversation view is off: Labels will only show on individual messages you labeled. If someone replies to that message, the label won’t show up on the reply.

If conversation view is on: When you label an entire conversation, the label will only show on existing messages, not new ones.

Let’s all get out our pitchforks and storm Google’s campus and demand that they right this wrong, shall we?