At the very same time that I unchecked this "cached exchange" option on one workstation, another user reported that his address book had now showed the changes to the names on the address list (and this is after having changed the name on exchange server over 24 hours ago).The strange thing to me is that I cannot understand why the second user mentioned saw the proper changes to the address book while still using the "cached exchange" option, meanwhile another user needed to have the option uncheked to see the changes.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.Full OAB download threshold To modify the threshold at which Outlook will download the full OAB rather than the incremental update, you can set the following Registry value Key: As the value, set at which relative size a full OAB download should take place rather than an incremental update.For instance, setting the value to 4 will trigger a full download when the incremental update is larger than one-fourth the size of the full OAB.
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.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.In a later section, it is explained how to modify this.There are various Registry settings available to control or modify the update and download behavior of the Offline Address Book in Outlook.The command for the manual update procedure can be found here: Outlook will automatically download updates only unless the size of the changes is larger than 12.5% (one-eighth) of the total OAB size.In that case the whole OAB is being downloaded again.Every time, Outlook kept showing me “Error 0x80200049” warning message.Apart from this, my Outlook is functioning absolutely fine. Can anybody tell me how to solve “Local Global Address List not Updating” issue? Thanks.” To many Outlook users, error code 0x80200049 when Outlook cannot update Global Address Book is a common one.Before moving to the solution part, it is necessary to confirm the cause of this error. Users can take help of this post and resolve the error by following instructions given here.Here is the way to find out if this error is caused by full BITS job list.