CryptoMix ransomware-affected file
File type: Ransomware encrypted file
A .lesli file is an original file encrypted and renamed by the CryptoMix ransomware.
The extension does not identify a separate usable file format. It marks a file affected by the ransomware.
File type category:
Ransomware encrypted file
Date updated: October 17, 2026
The .lesli extension was associated with a CryptoMix ransomware variant reported in late December 2016. The ransomware encrypts the contents of the victim's files and adds the .lesli suffix to their names.
The ransomware's recovery instructions are saved in a file named INSTRUCTION RESTORE FILE.TXT. The encrypted files remain unusable until they are successfully decrypted.
Avast Decrypter for CryptoMix is available for Microsoft Windows and may be able to restore files affected by this ransomware.
A .lesli file cannot normally be opened in the application that created the original file because its contents are encrypted. On Microsoft Windows, try Avast Decrypter for CryptoMix to decrypt it.
The INSTRUCTION RESTORE FILE.TXT file is a text file and can be opened with a plain-text editor to read the ransomware's instructions.
A .lesli file cannot be meaningfully converted while it remains encrypted. Use Avast Decrypter for CryptoMix on Microsoft Windows to attempt decryption first.
After successful decryption, the recovered file can be opened or exported with the application associated with its original file type.
Software apps that recover lesli files:
Microsoft Windows
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