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.
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.
Key: Note: As Outlook 2010 an Outlook 2013 can connect to multiple Exchange servers in a single mail profile, there is an additional “Offline Address Books” subdirectory which contains folders with GUID references which contain the actual oab-files.
Finding out which GUID represents which mail account isn’t very straightforward but looking at the “Date modified” value of the folder should give you a good indication if you don’t want to simply delete all folders or rename them to
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.
I know that this article could consider as “long and tedious” but the Murphy law dictates that: most of the Outlook synchronization problem accrues to “VIP Users,” that usually demand a solution!Furthermore, there is no way to edit the file where these names are stored since it isn't written in plain text. Nevertheless, you can delete entries from the cache one at a time when necessary. Outlook remembers up to 1000 email addresses you've used in the past, even if you have never stored them as Contacts. One benefit is that you can easily retrieve email addresses you have used just by typing the first few letters.A drawback is that as you update your contacts, the Auto Complete name cache file remains static.