If the update mechanism appears to be broken for you, it could be because of a corruption in your OAB or in your mail profile.
In that case, you can completely reset it by deleting the files making up the OAB or by recreating your mail profile.
They do for my colleague sitting next to me, so I don’t think it is a server misconfiguration or something like that.
Is there any way I can force a manual update of the Offline Address Book (OAB) in Outlook or reset it completely otherwise?
Rather than waiting 24 hours for Outlook to update the Offline Address Book on its own, you can force an update via the Send/Receive menu button.