The AutoComplete cache fetches commonly used email addresses when you type the first few characters in the To, CC or BCC box when you compose a message in Outlook. Below are the steps which will explain how you can remove entries from the AutoComplete cache.
A) To remove a single entry from the AutoComplete cache
1. Compose a new message and start entering the first few letters of the contact you want to remove from the cache.
2. Once Outlook suggests the contact, hit the DEL key on your keyboard.
B) To remove the entire AutoComplete cache
1. Close Outlook.
2. Start --> Run. Type "%Userprofile%\Application data\Microsoft\Outlook" (including the quotes) and click OK.
3. You will find an NK2 file named after each Outlook profile. Rename the NK2 file. (The NK2 file is your autocomplete cache file aka nickname cache file).
If you cannot find NK2 files, make sure you can see file extensions (Tools --> Folder Options --> Uncheck "Hide extensions for known file types")
