Extract text from Unknown files (UNK)
To convert UNK files to another format, you need Microsoft Outlook or other System software.
To convert other file formats to the "Missing Extension File" file type, you need software like Microsoft Outlook or a similar tool.
A .UNK file represents an "unknown" file type. Operating systems, email clients like Microsoft Outlook, and web browsers generate these placeholder files when an original file extension is missing, corrupted, or stripped by strict security filters. In a very specific scientific context, it may also be a spectrophotometer measurement data file used by Shimadzu UVProbe software, or occasionally a game package for The Sims 2.
The main disadvantage of a .UNK file is that standard operating systems like Windows or macOS do not know which application to launch when you double-click it. This completely blocks regular workflows. It forces users into a frustrating guessing game, trying to manually force the file to open in Microsoft Word or Adobe Acrobat Reader.
Users need to convert or rename this file because it is virtually useless in its current state. The best target format depends entirely on the hidden original format. In reality, the vast majority of .UNK files are actually ZIP-based Office Open XML documents (like DOCX), PDF files, PNG graphics, or JPG email attachments. Standard online converters fail with .UNK files because they rely entirely on the file extension to dictate the conversion path.
This file format is difficult to open because the extension itself is a generic placeholder, not a structural format. However, you do not need to guess. Our platform inspects the internal file signatures (the "magic bytes") to detect the true supported underlying format. If our analysis detects a supported embedded format, viewing or conversion to standard formats like PDF or JPG is completely straightforward.
Convert.Guru analyzes your UNK file, detects the exact format, and lets you read the text inside.
Users also converted UNKNOWN, UKN, JPG, PDF, PPTX, HTML, ZIP, SLDASM, INO and DAT files.
If you want to convert UNK file to TMP, TEMP, CACHE, LOG, BAK, OLD, NEW, PART, DOWNLOAD, CRDOWNLOAD, LOCK or PID, you can use Microsoft Outlook or similar software from the "Unknown File Placeholder" 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 UNK, try Microsoft Outlook or another comparable tool in the "Unknown File Placeholder" 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 UNK converter.