There is only one file type that uses the .OLK14PREF extension:
Outlook Preferences File
File created by Outlook for Mac, an email program first released in the 2011 Office suite for Mac; contains software preferences, which can specify composition and reading settings; saved and read automatically by the software.
OLK14PREF files are saved within the following directory in Mac OS X:
[user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Preferences/
Updated: March 5, 2011