How it works
Basically your auto complete cache is a collection from all the recipients in the e-mails you have send out.
Luckily the majority of users never cleans their outbox, so if you would walk through all mails in the “Send Items” box, copy all recipients to a blank mail and press the “Check Names” button….. your cache is rebuild.
The above can be a bit time consuming so I have written a small .NET program that can do the work for you. It uses the “.NET Programmability Support” in Outlook. So you must make sure that it is installed before you can use this program.
Enable Outlook Interop in setup office 2007
Install the program and start it
Start Program
Next click on the "Auto Rebuild" button, this will process your "Send Items" and your "Contacts" Folder
If you like to scan other folders then select those with the "Select Additional Folder" button before you press the auto Rebuild Button.
Allow access to Outlook
Your outlook will probably warn you that a progam is trying to access E-mail addresses. set it to allow access for 10 minutes and click OK
(while waiting feel free to click some advertisings on this site to pass the time)
Done Rebuilding
After a while it will finish and you can enjoy the autocomplete again.
Dont forget to close Outlook before you reboot. It seems some versions of outlook dont save the nk2 file if they are killed by a reboot.