Due to various synching schedules, it can take up to 48 hours before you could actually see a change in Outlook after a modification has been made on the Exchange server or in Active Directory.In this guide, the relevant timings are explained and instructions are given in how you can directly force an update and resync, which can be very handy when troubleshooting or when you work in an Exchange environment which sees a lot of user mailbox mutations.When you have Cached Exchange Mode enabled, Outlook by will by default cache the main Global Address List as well.This is called the Offline Address Book and is being generated on the Exchange server.Even though Outlook is the last in the chain, it is often the first level where the troubleshooting takes place as usually this is where the request is coming from.And since this website’s main focus is on Outlook, it makes sense to start with Outlook as well ;-).The only way to continue working is to leave the pop-up open and click on another window, giving it the focus. I set the Sonic WALL packet monitoring for all packets.
The amount of time it takes to complete varies depending on the number of emails, file size, and processing power.This means that in the worst possible scenario, an update to the Address Book won’t become available to the user until 48 hours after the change.This situation however is extremely rare since the default maintenance time on Exchange is at AM and updates and downloads are usually performed during working hours.Then I turned on a laptop with Outlook 2016 installed which, for a reason I don’t fully understand, had not updated its internal clock to the server’s time. And then it showed up on one of the formerly fixed Outlook 2016 clients.I rebooted the machine until it picked up the correct time, set it ot “work offline” mode, and dis the dame thing to the other Outlook 2016 client that had caught the disease. So I think the root cause was the wrong server clock, which caused the client’s clocks to be wrong, which caused Exchange to reject part of the automatic client login (but, strangely enough, not the whole thing).