Recently, when my Mac's date & time switched back an hour for auto daylight savings adjustment while Outlook was open and online, duplicate messages started appearing in Outlook.  These duplicates are not sync'd with the IMAP server, however, and appear to be an internal glitch where a 2nd instance of the message is displayed but not actually permanently created.  So what will happen is that a duplicate will randomly appear if the time is changed while the app is open (working either online or offline) and after deleting or moving the message, the copy lingers for a while and then just disappears as if it were moved manually. It happens in the Inbox very frequently now, where usually a few messages will have duplicates displayed.  If i look at the webmail server, those duplicates are not there.

This has happened before with other folders, such as the Sent folder, if i changed the time manually.  The only way it seemed i could resolve it was to create a new folder, move all the messages from the Sent folder into the new folder, delete the old folder and then rename the new folder "Sent".  This is obviously very glitchy.  I don't know how to fix the problem with the Inbox though b/c i'm not able to create a new Inbox folder and the "repair folder" option didn't work.

Deleting and recreating the account is not something i want to do as this resets all my custom folder column settings, which is a major problem... unless there is a way to migrate these to the new account after redownloading all the messages again from the server.