Since Outlook has a limit on how many folders can be synced at a time, there can be a queue of folders waiting. Outlook checks the server for updates every minute, any folder that has updates will subsequently be synced. If you carefully watch the progress during the sync of a folder with greater than a couple thousand messages, you will see 'Updating local.' a lot before the newer mail starts arriving (newer than the initial 512 that come down). This is also further exacerbated by an Exchange issue where it gets unnecessary change events before the newer mail arrives.

This is why it will look like you are not getting new mail when a folder is still going through initial sync. Due to the design of Outlook's sync engine (and how exchange works), you will see the 512 newest messages in a folder at the initial start of sync then the rest of the folder's contents will be back filled before you see any mail that arrives after this point. (this is the number one cause of problems with sync).ĭo NOT make sub-folders under the Inbox. All folders should be at root level.Īny folder with more than a few thousand messages is going to take some time to fully come down when you first sync your account. The Inbox syncs more frequently than any other and should be kept as clean as possible.