Needed to backup my contacts in Outlook, but it would not save the emails in the email “To” dropdown field, when autocomplete triggers. This is because it’s stored in Outlook’s NK2 cache file. This file is not in readable form, but you if you have the patience, you can view the emails if you don’t mind looking through funky ASCII characters of binary data. In the process of looking for and trying various tools, I realized that not all tools were able to extract all contacts. Keep this in mind.
There’s a few tools out there that you can use to extract a list of emails saved in the NK2 file. Here they are.
Ingressor – is the best program, I was able to extract the most amount of emails/contacts, but you have to pay for it. I think it extracts everything, but you can’t save anything or copy anything. Use OCR software?
Debunk2– It’s free, but it missed 1 (could possibly miss more on different NK2 files) contact.
NK2.info– It’s free, but it missed 2 contacts, and it doesn’t show the names accurately, like Debung2 and Ingressor.