If someday you can not find your mails, please make sure you check the other tabs also.
If you are a Gmail user, then you have noticed tabs in your inbox recently. Actually Google have introduced a new style of inbox with different tabs. Primary, Social, Promotions, Updates and Forums. Google automatically arrange your mails in these tabs to keep your inbox manageable. Your main mails are stored in Primary tab and others goes to other tabs depending your mail’s sender and Google’s algorithm. So if someday you can not find your mails, please make sure you check the other tabs also. You can also drag and drop mail to any tab of your choice. Google is saying that, this new feature is in Gmail so that you control your inbox and not the inbox controls you with so many different mails in one place. If you are using Priority Inbox or other types of inbox like Important First or Starred First, then tabbed inbox is not going to be much helpful to you. You can stick to your old style of inbox if you are not like tabbed inbox.
We always welcome new change from Google. Lets see this new feature can help user or not! You can read the official post here.