How To Reset The Outlook Address Cache

How To Reset The Outlook Address Cache

If you are typing email addresses into your Outlook and they have gone wonky there are several things you can do but the easiest is likely just to flush the Outlook Address autocomplete cache.  In old versions of Outlook, that meant deleting the .NK2 file from %appdata%\Microsoft\Outlook however in Outlook 2016 (actually since Outlook 2010) your ‘nickname’ cache is stored in %localappdata%\Microsoft\Outlook\RoamCache

There are three easy ways to empty the Outlook Autocomplete Email Address Cache:

1. Flush The Outlook Email Address Cache Using File Manager:
Close Outlook
Using File Explorer, MY PC, THIS PC or whateva’, go to %localappdata%\Microsoft\Outlook\RoamCache
Delete Stream_Autocomplete_0_.dat 
Open Outlook
Have a nice day

2. Flush The Outlook Email Address Cache Using the Outlook GUI:clear-autocomplete-outlook-address-cache
Open Outlook
Click FILE
Click OPTIONS
Click MAIL
Scroll down about half way and select EMPTY AUTOCOMPLETE button
Have a nice day

3. Flush The Outlook Email Address Cache Using Command Line:
outlook.exe /cleanautocompletecache
Have a nice day
If you have any questions, post them here or read:

https://www.slipstick.com/outlook/email/understanding-outlooks-autocomplete-cache-nk2/
https://grok.lsu.edu/article.aspx?articleid=18029