U2K is a ransomware infection. It encrypts files and renames them by adding the “.u2k” extension. U2K also creates “readme.txt” files with ransom demands. The .u2k extension can be used by various programs, not just ransomware. Other potentially harmful software may also create .u2k files. Be cautious with .u2k files from unknown sources.
When you double-click a .u2k file, Windows may not recognize the extension. Then you cannot open the file by double-clicking. If you know another program that opens .u2k files, try selecting it.
U2K sneaks into systems without symptoms. Users notice the infection when files are already encrypted. U2K typically enters through infected programs, cracked games, fake updates etc. It encrypts files and appends the .U2K extension. For example “photo.jpg” becomes “photo.jpg.U2K”. U2K also creates ReadMe.txt files with ransom payment instructions.
Identifying ransomware by the appended extension works only when the extension is unique. Generic extensions like .encrypted or .locked make identification impossible. Use the ID Ransomware website to quickly identify most ransomware.
Unknown Software