TeslaCrypt 4.2 ransomware: what it is and how to remove it

Not before you have tried everything else. Identify the family from RecoveR!-[5_characters]++.HTML and one encrypted file, check No More Ransom for a free decryptor, and look for clean copies in OneDrive, backups and Previous Versions.

Paying funds further attacks, may be illegal if the group is sanctioned, and is no promise of a working key: many victims get partial or broken decryption. If you consider paying for business-critical data, involve the police and a professional incident responder first, and never pay through intermediaries who promise their own decryption.

Nobody can promise a date. When we last checked, on 7 October 2026, no free decryptor is known. Decryptors usually appear after one of three events:

• police seize the attackers' servers and keys
• the authors leak or publish the master keys
• researchers find a mistake in how the ransomware generates keys

Some families got a tool within weeks, others never. Keep the encrypted files and the note on an external drive, check No More Ransom every few months, and follow news about the TeslaCrypt 4.2 family. A decryptor may need an original file, so keep any unencrypted copies too.

Only if a decryptor already exists or the company pays the attackers for you. Some "ransomware recovery" services advertise that they can decrypt families with no known flaw; in practice they negotiate with the attackers and add their own fee. Others use the same free tools listed on No More Ransom.

Before you hire anyone, ask in writing how they will recover the files, whether they will contact the attackers and what happens if they fail. A legitimate service answers clearly. If a free decryptor exists for your family, you can run it yourself.

The way TeslaCrypt 4.2 spreads has not been documented yet, so look at your own recent activity. On home PCs, ransomware most often comes with cracked programs, game cheats, key generators and fake updates, or with an e-mail attachment that was opened. On business networks, attackers usually log in through Remote Desktop with a stolen or guessed password.

Think back to what was downloaded or installed in the days before ransom notes called RecoveR!-[5_characters]++.HTML in every folder, and check the Downloads folder and Installed apps sorted by date. Keep anything suspicious for your report, but do not run it again.

We do not know yet. Nothing published so far shows data theft by TeslaCrypt 4.2, but the only confirmed sign is ransom notes called RecoveR!-[5_characters]++.HTML in every folder, which says nothing about what happened before. Many current ransomware attacks copy files or run a password stealer first, so it is wise to act as if they did.

From a clean device, change the passwords that were saved in the browsers on this PC, starting with e-mail and banking, sign out of all sessions and turn on two-step verification. Watch bank statements and account activity for the next few weeks.

Not necessarily. Ransomware names come from the file extension, the note or a word in the code, so unrelated families often end up with similar names, and one family can appear under several names. The difference matters: a decryptor or advice for one family does not fit another and can damage files.

Compare the ending added to your files and the exact name of the note with the summary table at the top of this guide, then upload the note and one encrypted file to ID Ransomware from a clean device. If the result names another family, follow the guide for that family instead.

Quite a lot. The file name RecoveR!-[5_characters]++.HTML, the wording, the contact addresses and the format of the personal ID are typical for each family. Uploading the note together with one encrypted file to ID Ransomware or No More Ransom's Crypto Sheriff usually names the family within seconds.

That name decides your options: some families have free decryptors, some can be partially recovered, and some cannot be decrypted at all. The note's claims about stolen data should be taken seriously but not at face value.

In the best case, the attackers send a decryption tool and a key, and the tool works on most files. In many cases it does not go that smoothly:

• tools crash on large files
• skip some folders or are painfully slow
• some attackers simply stop answering after payment or ask for more

You have no way to enforce the deal. Paying also tells criminals that you pay, which makes a second attack more likely. If you are still considering it, report the attack first, keep copies of all encrypted files and never deal through an intermediary who contacted you.

You cannot open locked files normally while they stay encrypted, and renaming them will not help. Our earlier report did not record the extension that TeslaCrypt 4.2 adds, so check one locked file name and the ransom note for it.

No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates. Do not rename the files, change the extension or edit them, because that can make recovery harder. Copy the locked files to an external drive before you clean the system, so a decryptor released later still has them.

Fortect scans Windows for malware and unwanted programs and repairs the system files and settings they change, and its free scan shows what it finds on your PC before you decide anything.

For TeslaCrypt 4.2, follow the plan above as well: the browser steps take back permissions and settings that no scanner treats as a threat, and uninstalling the program that brought it removes the source.

Run Microsoft Defender's full scan and, if anything was found, its offline scan as a second opinion. If the symptoms are gone after the plan and both scans are clean, there is nothing more to do.