How To Clear the Outlook Email Address Auto Complete Cache

For some reason, the auto-complete in my Outlook 2010 has gone screwy and started having the incorrect addresses for auto-complete entries.There are several options but as this is a relatively new install of Outlook, I'm going to nuke the cache. "That would make a good blog post" I thought to myself, so here goes.

It's actually surprisingly easy too and works for Outlook 2003, 2007 and 2010.

Outlook 2010 Method

1. In Outlook 2010, click File and then click Options.
2. Click the Mail tab.
3. Under Send Messages, click Empty Auto-Complete List.

Outlook 2003/2007 Method

1. Make sure Outlook is closed.
2. Open Windows Explorer and browse to %APPDATA%\Microsoft\Outlook (or just copy and paste it into the address bar).
3. Rename Outlook.nk2 to outlook nk2.bak (just in case you need it ever again)
4. Thats it. There is no step 4 :-)

For a more in-depth look at the various options related to Outlook auto-complete cache, look at this KB article which has every permutation of config steps known to man.