Renaming just a single or some of the files will result in an OAB corruption. A benefit of manually deleting the oab-file is that before they are being re-downloaded, you are working with the Online Address Book.
When you find things working correctly for you now but not anymore after the oab-file were redownloaded, you know that the issue is with the oab-files on the server and not on the client or the Address Book configuration in general.
And since this website’s main focus is on Outlook, it makes sense to start with Outlook as well ;-).
When you update an Offline Address Book on the Exchange server via the Exchange Management Console or the Exchange Management Shell, one would suspect that updating the Outlook client after that would directly get you this fully up-to-date copy. After the OAB gets updated on Exchange, it still needs to distributed to the web services first, even in a single server environment.
The process of updating and distributing the OAB is achieved by the following two schedules.
The users that were not able to sync their address books were all on the same database.
That mailbox database was pointing to an Offline Address Book that was not serving the OAB over HTTPS, it was Public Folder only.