Ghost Emails "Unread" from Gmail on iOS Mail App

I was facing a similar problem too but here was my situation and my fix. First I had an unread counter of thousands next to my gmail mailboxes in apple mail on iOS devices. I had no unread in my apple mail unread folder. Then I went to gmail on browser and there was an unread count next to my folders. I tried to select all mail and even tried select all with the option to include additional messages across server. Then I did a bulk mark read, it said loading for a while but the numbers didn’t change. I finally figured out I entered is:unread in the search and there were unread messages. I did a bulk mark read after selecting all messages matching search ( you have to click this option not just the check all or it will just look at your 50 or 100 messages on the screen. The counter went down about 10k records and new messages popped up on my gmail in browser. I repeated this task until no unread number next to mailbox on gmail and checked Apple and the unread counter disappeared !!! There are a few features/ bugs going on here : 1) Apple mail accurately reflects unread count but doesn’t poll in the full history of unread messages so it might show up empty even though there are in google. 2) Google also has an accurate unread count but it’s confusing that you need to first search the entire population with the search, not just use a select but select additional matches and the bulk action feature only works for a few thousand messages at a time then gives up. I hope this helps at least a few people !!

-Matt

Check your deleted, archived and other folders for unread mails. I usually select all mails and mark all as read (easier on a computer)