Mailbox Migrations and the Frequently Used Email Cache

Posted on 2008-10-30
Last Modified: 2010-04-07

Ever since Microsoft invented that "frequently used email cache" in Outlook, migrating users from one server to another has become problematic.  Once a user is moved, other people using Outlook 2003+ can no longer use the cached email information that is stored in the .nk2 file.  When messages are sent using those entries, the sender receives an NDR.  Instead, we have been coaching people to select the user from the GAL.

We are currently planning a migration from Exchange 2003 to 2007 which will entail moving all of our users in North America.  I wanted to see if anyone had some recommendations on how to handle this situation because forcing people to temporarily stop using this autofill feature will not go over all that well.  

What are other Exchange administrators doing about this?
Question by:rujeff80
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LVL 32

Accepted Solution

gupnit earned 500 total points
ID: 22846331
You can use Group Policies with small script to delete the .NK2 files from users Profiles.
That is as easy it will get without user intervention
Hope this helps, please let me know
LVL 15

Expert Comment

ID: 22846632
yer i agree, the night of the migration, delete all the .nk2 files...

if your using exprofre to redirect exchange profiles - that has an option for deleting nick files when updating the profile.

If your lucky enough not to have to bother with updating profiles (same admin group) - then yer, use SCCM to WOL every machine, delete every nk2 you can find.

Author Comment

ID: 22851316
I was hoping to avoid having to delete the file from everyone's computer.  I want to keep this topic open a little longer to see if anyone has another way of doing this.

Thanks for your help so far.

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LVL 32

Expert Comment

ID: 22851920
Well deleting NK2 file take care of issue, I am not sure what else are you expecting.
Please let me know, maybe I am not in sync

Author Comment

ID: 22852534
I was just hoping there would be an alternative to deleting the nk2 file, maybe there was some sort of dynamic update or something that could be performed or MS had some kind of tool.  Having to delete the .nk2 file for everyone seems extreme just to have a mailbox moved.
LVL 32

Expert Comment

ID: 22852823
Well, there is no option to dynamically update NK2 files provided. And deleting is going to be done using GPO, so no hassle, this is what is done everywhere :-)!
Still you can keep your question open for comments (if any)

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