Extract text from Outlook AutoComplete files (NK2)
To convert NK2 cache files to another format, you need Microsoft Outlook or other Data software.
To convert other file formats to the "Email Contact Cache" file type, you need software like Microsoft Outlook or a similar tool.
The .NK2 file is a legacy proprietary binary format used by older versions of Microsoft Outlook (primarily 2003, 2007, and 2010) to store the "AutoComplete" nickname cache. This file contains the list of names and email addresses that automatically populate when you begin typing in the "To" or "Cc" fields.
A common problem for users is that .NK2 is a binary file, meaning it cannot be opened or read in text editors like Notepad or spreadsheet software like Microsoft Excel. Furthermore, modern versions of Outlook (2013, 2016, 2019, and 365) have abandoned this format in favor of storing AutoComplete data directly in the mailbox or as Stream_AutoComplete_*.dat files. This leaves many users with orphaned .NK2 files from old backups containing valuable contact information that is otherwise inaccessible.
To retrieve this data, users typically need to convert the .NK2 file into a standardized format. For data recovery and list management, converting to CSV (Comma Separated Values) is the best approach, allowing you to view, sort, and edit the email addresses in spreadsheet software. For migration, the file often needs to be processed by specific import command-line switches to be ingested by modern Outlook versions.
Convert.Guru analyzes your NK2 file, detects the exact format, and lets you read the text inside.
Users also converted DAT, CSV, PST, PRF and OAB files.
If you want to convert NK2 file to CSV, TMP, TEMP, CACHE, LOG, BAK, OLD, NEW, PART, DOWNLOAD, CRDOWNLOAD or LOCK, you can use Microsoft Outlook or similar software from the "Outlook AutoComplete Cache" category. In the File menu, look for Save As… or Export….
To convert DEVICE, CACHE, SOCK, SYMLINK, PID, MOUNT, FIFO, LOG, PIPE, TMP, JUNCTION or TEMP files to NK2, try Microsoft Outlook or another comparable tool in the "Outlook AutoComplete Cache" category.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our NK2 converter.