I was having a similar issue as this and found a solution I figured I would share here.
In my case, the user has access to multiple mailboxes and was caching all of them. Which seemed to cause problems with immediate updates while the user was using Outlook.
What I did
- I went into my user's account settings to
- Opened up
- Then went to the
Advanced tab and unchecked
Download shared folder under the Cached Exchange Mode Settings
This fixed my problem, although I am not sure if this fix is applicable to everyone.
Bear in mind
Cached Exchange Mode stores a local cache of your outlook files and folders on your local machine in an
.ost file. This allows for users to use and manipulate their emails even when offline.
Turning this feature off, while it may fix the problem, will prevent users from viewing or using their email while offline. While the
Download shared folders options will only do it for the extra mailboxes the user is given permission to in Exchange.
Extra: Shortening the amount of time it caches could also help.