In a mailbox hosted by Google for a domain I own, one email from someone with whom I regularly correspond refuses to appear in 'Inbox'. I can only see it in All Mail. Any attempt to move or copy it to Inbox vanish and (if moved) reappear a second later back in All Mail as though it were the subject of a filter. When forwarding or replying, it *does* appear in Sent Items. And refuses to be copied or moved from there too. Any replies to that email thread from both the originator and my business partner Cc'ing me also only end up only in All Mail and cannot be moved. I've tested any number of permutations of replying to and forwarding that email, right up to the extreme of deleting all content, changing the subject and sending it to myself at another email, then replying back. STILL it stubbornly refuses to appear in Inbox. Just to be sure I switched off my 3 pretty mundane filters which were all clearly not at fault. The emails appear in my phone's inbox just fine so aren't being sent to Spam or any of the other Gmail-specific folders. I've discovered a magic email. I should get in touch with Q branch... although they probably wouldn't see the email. It's truly bizarre. Any ideas?