Nuke ransomware-affected file
File type: Ransomware encrypted file
A .nuclear55 file is an encrypted and renamed file affected by a variant of Nuke ransomware.
The extension may be added to documents, photos, archives, and other files after the ransomware encrypts them.
File type category:
Ransomware encrypted file
Date updated: October 6, 2026
The nuclear55 file extension is associated with a variant of Nuke ransomware that reportedly began using it around October 2016.
A .nuclear55 file contains the encrypted contents of the original file, such as a document, photo, archive, or another type of user file. The extension is added when the ransomware renames the affected file.
Because this is a ransomware-specific filename extension rather than a normal file format, it is not intended to be opened independently. Recovery depends on a working decryptor, an available backup, or another safe recovery method.
A .nuclear55 file cannot normally be opened with the application that created the original file because its contents have been encrypted by Nuke ransomware.
There is no general-purpose program that opens these files. After successful decryption, the recovered file should be opened with the application appropriate for its original format.
If no decryptor or backup is available, the remaining option may be to pay the ransom, which may not work and may be a scam.
A .nuclear55 file cannot be meaningfully converted while it remains encrypted. It must first be decrypted or restored from a backup.
Once recovered, the resulting original file may be converted with software that supports its original format.
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