CryptoLocker encrypted file
File type: Ransomware encrypted file
A .cryptolocker file is a user file encrypted by the CryptoLocker ransomware and given a .cryptolocker suffix. It is not a normal document format and cannot usually be opened by the program that created the original file.
File type category:
Ransomware encrypted file
Date updated: October 12, 2026
The .cryptolocker file extension is associated with CryptoLocker, malicious ransomware that targeted Microsoft Windows computers. CryptoLocker was among the first widely known ransomware threats to spread through malicious email attachments and botnets.
CryptoLocker encrypted selected types of files on local disks and mounted network drives using RSA-based public-key cryptography. A .cryptolocker file contains the encrypted contents of the original file, whose name and extension were changed by the ransomware.
CryptoLocker is no longer an active software product and has no legitimate vendor. A separate ransomware family reported in December 2016 also used the CryptoLocker name, but it came from a different group and should not be assumed to use the same encryption or recovery method.
A .cryptolocker file cannot be opened normally with a document, image, archive, or media program. Renaming the file does not decrypt it.
There is no reliable decryptor for CryptoLocker. Recovery may require a decryptor that supports the particular CryptoLocker infection and access to the required key; otherwise, consult a reputable malware-recovery or incident-response specialist and restore the original file from a clean backup if one is available.
A .cryptolocker file cannot be meaningfully converted while it remains encrypted. It must first be decrypted or replaced with an intact copy of the original file.
After successful decryption, the recovered file can be opened and converted using software that supports its original filename extension and format.
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