Open up the latest log file in the directory and see what errors are being reported by the client.
In our case, we had these error messages: Notice the error “Is Local OABFile Current: Manifest Enforcement Disabled And Local File Too Old”.
The reason this happens is that that when one or more OAB Version 4 offline address book files are corrupted or missing.
In this case, the Microsoft Outlook clients cannot download the updated files until the issue is resolved.
Because the files were not changed recently the error message was downloaded and the client could not download the files.
So we decided to remove the copy and then create a new database copy. With a single, good database copy, we can now generate, update and download the Offline Address Book.What ended up happening is about a day later if a user tried to manually download the address book, they would not be able to and would get a 0x80190194 error: Troublshooting So what is this? Well, let’s look at the log files for OAB downloading.In Exchange Server 2013, these files are located in the %Exchange Install%\Logging\OABDownload directory.We should also check to make sure we can update the OAB using Power Shell.So, first, check to see where the mailbox is: Which gives us this result: Then we can check and the database is mounted: Next we can try to update the files for the OAB.