Q. When I check Gmail on the web, my messages all arrive in the inbox, but then move themselves to All Mail within a few minutes. What causes this?
A. Software glitches have been known to happen, but a mail filter or an account setting in your Gmail preferences may be causing incoming messages to move into the All Mail area. As its name indicates, this is where all the messages in your account can be found, including mail that has been archived or conversational threads that you have muted.
If you set up your Gmail account on multiple devices — like a smartphone or tablet — or on another computer using a stand-alone mail program, settings for those mail apps and programs may be affecting which messages get moved from the Inbox to the All Mail area.
In your Gmail account settings on the web (available under the gear-shaped icon on the right side of the browser window), click the “Forwarding and POP/IMAP” tab to see what the software has been instructed to do with messages read on other screens. If you have set up filters for your incoming messages, click the “Filters and Blocked Addresses” tab to see if any filters are set to archive copies of certain messages.
If you are not sure if another device is interfering with your incoming mail, try changing your password on the Gmail website; on the Settings screen, click “Accounts and Import” and then click the Change Password link in the “Change Account Settings” area. Without the updated password, other apps and devices will not be able to download new Gmail messages and if your inbox stays as you left it, you know one of those other programs was the culprit.