TeslaCrypt 4.1b ransomware: what it is and how to remove it
The security experts have recently issued a report that a new TeslaCrypt 4.1b version of the notorious TeslaCrypt virus was released. We want to inform the readers who are not yet aware of this virus that it is a program you should avoid by all means.
Facts checked October 7, 2026. Removal steps tested on Windows 11 (26H2) and checked against Microsoft's and the browser makers' current documentation. Sections marked as our earlier report are the original text: they describe the threat as it was then and have not been reviewed since. The 2026 status, the removal steps and the questions are current.
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TeslaCrypt 4.1b ransomware: summary
| Detection names | No Microsoft detection name is known |
|---|---|
| Ransom note | Not named in our report; the text of the note is not in our records |
| Contact | Not recorded in our earlier report |
| Encrypted file extension | Not recorded in our earlier report |
| Decryptor | No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates |
| Distribution | Not recorded in the old report |
| Removal | Scan the PC with security software to find and remove the malware and anything installed with it. Fortect scans Windows for malware and repairs the system files and settings it damaged. Remove it nowTo use the full-featured product, you have to purchase a license for Fortect. The scan is free. |
Show 8 more facts
| Damage | Not recorded in the old report |
|---|---|
| Name | TeslaCrypt 4.1b |
| Type | File-encrypting ransomware |
| Symptoms | An unknown program in Installed apps |
| Evidence | One write-up by a security site; details still limited |
| Free decryptor | No free decryptor is known (checked 7 October 2026) |
| First seen | 26 April 2021 |
| Facts checked | 7 October 2026 |
How TeslaCrypt 4.1b ransomware behaves
From our report of Apr 2021 · not reviewed since
What is new with the TeslaCrypt 4.1b virus version?
The security experts have recently issued a report that a new TeslaCrypt 4.1b version of the notorious TeslaCrypt virus was released.
We want to inform the readers who are not yet aware of this virus that it is a program you should avoid by all means. It is a ransomware-type virus, which means that once it infiltrates the computer, it scans it for files, encrypts them with a complex algorithm and asks the victim to pay a considerable amount of money to receive the access to the locked files.
TeslaCrypt has already released TeslaCrypt 2.0, TeslaCrypt 3.0 and TeslaCrypt 4.0, which featured some minor modifications in the amount of ransom offered from the users and improving their encryption, with each version making the file decryption increasingly more difficult.
It is possible that the virus may as well update itself to the latest version while residing on the PC, so it essential to remove TeslaCrypt 4.1b ransomware from the computer before you face even more destructive consequences.
You can try using sophisticated antivirus tools like for this purpose, but you have to be aware that the virus may try blocking the antivirus from working, so it might need some extra help to initiate.
TeslaCrypt version 4.1b is a very recent update to this program, and few users are infected by it; therefore, the researchers are still working on determining what has specifically changed since its previous versions. It seems that in the newest version, the ransom notes the victims find on every folder containing infected data retain their former filenames:
- -!RecOveR!- ++.Txt
- -!RecOveR!- ++.Png
- -!RecOveR!- ++.Htm
What is new about this program are a couple of new gateway hosts, p23cb.bobodawn.at and y4bxj.adozeuds.com added to the list of websites where the victim can transfer the ransom. Of course, the demand to pay in BitCoins also remains. The current TeslaCrypt version also uses C:\Windows\system32\wbem\WMIC.exe shadowcopy delete /nointeractive command to delete the Shadow Volume Copies of the files on the victim's computer.
However, it is not certain if this WMIC (Windows Management Instrumentation Command-line) has not been used by the previous versions of the virus as well. Either way, the occurrence of new versions of TeslaCrypt ransomware only prove that the virus creators are continuously working on improving this program to bring even more trouble to its victims and antivirus software developers.
We have to point out again that TeslaCrypt 4.1b removal is essential to help stop such malicious programs from spreading because the more people get convinced into paying for their files, the more profit, and motivation the ransomware creators receive.
From our report of Apr 2021 · not reviewed since
How can this ransomware infiltrate my computer?
It has not been noticed yet if the TeslaCrypt 4.1b version spreads any different that its previous versions.
So, this means you can get infected if you are not careful about opening newly received emails. Usually, TeslaCrypt will arrive at your computer in a spam email as an attached JavaScript file named invoice_2h04qd.js. DO NOT download or open this file if it turns up in your email. The email itself might try to convince you that the attached file contains some important information, but beware!
The file carried a code which, when activated, downloads TeslaCrypt 4.1b into your computer. Usually, suspicious emails like these are automatically sent to the "Spam" folder by your email provider; however, you can never be sure that these malicious programs will not slip to your regular inbox as well. Therefore, it is necessary to equip your computer with the best antivirus software and try to act more cautiously online yourself.
The TeslaCrypt 4.1b ransomware note
We did not record the full text of the ransom note in our report.
How to remove TeslaCrypt 4.1b ransomware
Tools you'll need
All of these are free except where noted. Download them on a clean device if the infected PC is offline.
- A USB stick: to keep the ransom note, two or three encrypted files and screenshots off the infected PC.
- Microsoft Defender Offline: built into Windows 11 and Windows 10; scans before Windows starts, so running malware cannot hide.
- Microsoft Safety Scanner: a second, portable scanner with current signatures; each download works for 10 days.
- ID Ransomware: identifies the family from the note and one encrypted file and says whether a decryptor exists.
- No More Ransom: the free decryptors from police and security companies; check it again every few months.
- Fortect (optional): scans Windows for malware and repairs the system files and settings it damaged. The free scan is in the box above.
How to remove TeslaCrypt 4.1b and get your files back
Work in this order.
Disconnecting comes first, removal comes before any restore, and nothing here asks you to contact the attackers.
Step 1: Disconnect the PC and unplug backup drives
Unplug the network cable or turn off Wi-Fi, and disconnect USB drives, external disks and network shares, so TeslaCrypt 4.1b cannot reach more files. Pause OneDrive, Google Drive or Dropbox sync, because synced folders upload the encrypted copies over the good ones.
Leave the PC on but offline while you read the next steps, since a restart can let the ransomware run again. This applies to Windows 11 and Windows 10 alike.
Windows 11: turn off Wi-Fi to take the PC offline. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 2: Save the ransom note and identify the family
The name of the family decides whether a free decryptor can help. Copy the ransom note and two small encrypted files to a USB stick, and check them on another device with ID Ransomware or Crypto Sheriff.
Note the extension added to the files, the contact address and the victim ID shown in the note. Keep the originals on the Windows 11 or Windows 10 PC untouched.
Windows 11: the ransom note and encrypted files to copy for identification. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 3: Check for a free decryptor
Our last check found that for TeslaCrypt 4.1b, no free decryptor is known (checked 7 October 2026). Look again yourself in the No More Ransom list and the free decryptor pages of Emsisoft, Avast and Kaspersky, which add new families every year.
A decryptor needs the ransomware gone first, or it encrypts the files again. Keep at least one copy of the encrypted files on an external drive, even if no tool works yet.
Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 4: Remove the ransomware before you restore or decrypt
Removing TeslaCrypt 4.1b does not bring the files back, but it has to come first. Start with Defender's Full scan, then the offline scan from the same Scan options page, which checks the disk before Windows loads.
If the scan cannot start, use Safe Mode with Networking. Delete the ransom notes only after you have saved a copy, because removal tools sometimes leave them behind on Windows 11 and Windows 10.
Windows 11: Windows Security > Virus & threat protection > Scan options. Full procedure with screenshots: Run a Microsoft Defender Offline scan
Step 5: Look for shadow copies of the files
Windows keeps shadow copies for restore points and backups, and some ransomware fails to delete them.
vssadmin list shadowsin an administrator Command Prompt tells you at once whether any exist.If they do, right-click the folder that held your files, open Properties > Previous Versions, select a version from before the attack, and click Open to check it before you Restore or copy the files out. Windows 11 and Windows 10 both have the tab.
Windows 11: vssadmin list shadows shows whether shadow copies exist. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 6: Restore the files from a backup or recover deleted originals
A backup made before the attack is the surest way back. Connect it only once the PC is clean, then restore from File History, Windows Backup, OneDrive's Restore your OneDrive or your own external copies.
Without a backup, try file recovery: the originals that TeslaCrypt 4.1b deleted may still be on the disk until something overwrites them. Install nothing new on the drive you want to recover from on the Windows 11 or Windows 10 PC.
Full procedure with screenshots: Recover deleted files (Recycle Bin, backups, OneDrive) On uGetFix
Instructions for each browser and system
The detailed steps for every browser and system this guide covers. Open the one you use.
Manual removal using Safe Mode
Important! →
Manual removal guide might be too complicated for regular computer users. It requires advanced IT knowledge to be performed correctly (if vital system files are removed or damaged, it might result in full Windows compromise), and it also might take hours to complete. Therefore, we highly advise using the automatic method provided above instead.
Step 1. Access Safe Mode with Networking
Manual malware removal should be best performed in the Safe Mode environment.
Windows 7 / Vista / XP
- Click Start > Shutdown > Restart > OK.
- When your computer becomes active, start pressing F8 button (if that does not work, try F2, F12, Del, etc. - it all depends on your motherboard model) multiple times until you see the Advanced Boot Options window.
- Select Safe Mode with Networking from the list.
Windows 10 / Windows 8
- Right-click on Start button and select Settings.
- Scroll down to pick Update & Security.
- On the left side of the window, pick Recovery.
- Now scroll down to find Advanced Startup section.
- Click Restart now.
- Select Troubleshoot.
- Go to Advanced options.
- Select Startup Settings.
- Press Restart.
- Now press 5 or click 5) Enable Safe Mode with Networking.
Step 2. Shut down suspicious processes
Windows Task Manager is a useful tool that shows all the processes running in the background. If malware is running a process, you need to shut it down:
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Click on More details.
- Scroll down to Background processes section, and look for anything suspicious.
- Right-click and select Open file location.
- Go back to the process, right-click and pick End Task.
- Delete the contents of the malicious folder.
Step 3. Check program Startup
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Go to Startup tab.
- Right-click on the suspicious program and pick Disable.
Step 4. Delete virus files
Malware-related files can be found in various places within your computer. Here are instructions that could help you find them:
- Type in Disk Cleanup in Windows search and press Enter.
- Select the drive you want to clean (C: is your main drive by default and is likely to be the one that has malicious files in).
- Scroll through the Files to delete list and select the following:
Temporary Internet Files
Downloads
Recycle Bin
Temporary files - Pick Clean up system files.
- You can also look for other malicious files hidden in the following folders (type these entries in Windows Search and press Enter):
%AppData%
%LocalAppData%
%ProgramData%
%WinDir%
After you are finished, reboot the PC in normal mode.
From our report of Apr 2021 · not reviewed since
TeslaCrypt 4.1b removal recommendations
You may have to use the manual guide provided below to help your antivirus start and remove the virus.
You also have to keep in mind that if you have some backup files on an external drive that you want to restore on your computer, you have to make sure that the TeslaCrypt 4.1b removal was completed thoroughly. However, the easiest way to decrypt your files is to install this TeslaCrypt decryption tool and let it recover your files for you.
Report it and recover your files
Report it
Report the attack even if you do not expect the files back: insurers and banks ask for the report number, and police use the contacts in the note to link cases.
- United States
- FBI IC3 · FTC ReportFraud
- United Kingdom
- Report Fraud (formerly Action Fraud) · NCSC
- Australia
- ReportCyber (ASD)
- EU countries
- Europol: national reporting sites
Give the victim ID, the note and the date the files were encrypted. A business that holds personal data may also have to notify its data protection authority, in the EU within 72 hours.
Protect the files you restore
Restore only after the scans are clean and the PC no longer shows teslaCrypt 4.1b in the list of installed apps; otherwise the restored copies can be damaged again.
Then build a backup that survives the next infection:
- one copy in the cloud with version history
- one on an external drive that is disconnected between backups
- the working copy on the PC
Version history matters because a backup that syncs damaged files overwrites the good ones.
How to do this with the tools built into Windows: the 3-2-1 backup rule on Windows.
Stream videos without limitations, no matter where you are
There are multiple parties that could find out almost anything about you by checking your online activity.
While this is highly unlikely, advertisers and tech companies are constantly tracking you online. The first step to privacy should be a secure browser that focuses on tracker reduction to a minimum.
Even if you employ a secure browser, you will not be able to access websites that are restricted due to local government laws or other reasons. In other words, you may not be able to stream Disney+ or US-based Netflix in some countries. To bypass these restrictions, you can employ a powerful VPN, which provides dedicated servers for torrenting and streaming, not slowing you down in the process.
Data backups are important - recover your lost files
Ransomware is one of the biggest threats to personal data.
Once it is executed on a machine, it launches a sophisticated encryption algorithm that locks all your files, although it does not destroy them. The most common misconception is that anti-malware software can return files to their previous states. This is not true, however, and data remains locked after the malicious payload is deleted.
While regular data backups are the only secure method to recover your files after a ransomware attack, tools such as can also be effective and restore at least some of your lost data.
Questions about TeslaCrypt 4.1b ransomware
Is there a free TeslaCrypt 4.1b decryptor?
We last checked on 7 October 2026, and for TeslaCrypt 4.1b no free decryptor is known. We check No More Ransom, which collects free tools from police and security companies, and the decryptor pages of the major antivirus vendors. A working decryptor exists only when the encryption has a flaw or the keys were leaked or seized.
Ignore sites and videos that offer a "TeslaCrypt 4.1b decryptor" for download or for a fee: these are usually scams or malware. Real decryptors are free and come from known security companies or law enforcement. Keep the encrypted files in case a tool appears later.
Are ransomware recovery services legitimate?
Some are, but read the offer carefully. Genuine data-recovery firms recover deleted originals from disks or rebuild damaged files, and they say so. Others promise to "decrypt any ransomware" for a fixed price, which is impossible without the key; they quietly pay the attackers and keep a margin, sometimes without telling the victim.
Be especially careful with services that contact you after you post about the attack online. Ask for references, a written method and a no-result-no-fee clause, and check the free tools on No More Ransom first.
Should I pay the ransom?
We advise against it, and so do the FBI, Europol and national cyber agencies. Payment does not guarantee a working tool: some attackers never reply, some tools damage files, and some variants have no decryptor at all. Paying also funds further attacks and can make you a target again.
Before considering payment, try every recovery option in this guide and report the attack. Companies must involve their legal adviser and insurer, because payments to sanctioned groups can be illegal. If files are truly irreplaceable, store the encrypted copies and wait; decryptors sometimes appear later.
How did TeslaCrypt 4.1b get on my computer?
The way TeslaCrypt 4.1b 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 teslaCrypt 4.1b in the list of installed apps, and check the Downloads folder and Installed apps sorted by date. Keep anything suspicious for your report, but do not run it again.
Did TeslaCrypt 4.1b steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by TeslaCrypt 4.1b, but the only confirmed sign is teslaCrypt 4.1b in the list of installed apps, 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.
Is TeslaCrypt 4.1b the same as other ransomware with a similar name?
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.
How do I open my .docx, .jpg and other files locked by TeslaCrypt 4.1b?
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 4.1b 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.
What is TeslaCrypt 4.1b ransomware?
The security experts have recently issued a report that a new TeslaCrypt 4.1b version of the notorious TeslaCrypt virus was released. We want to inform the readers who are not yet aware of this virus that it is a program you should avoid by all means.
The summary table at the top of this guide lists the type, the detection names, the symptoms and the damage of TeslaCrypt 4.1b. Reading it first helps you decide whether your computer shows the same signs. The removal plan below it works in order, from the safest step to the more thorough ones.
Will Fortect remove TeslaCrypt 4.1b?
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 4.1b, 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.
Sources
- CISA: StopRansomware (read October 7, 2026)
- No More Ransom (read October 7, 2026)
- FTC: How to recognize, remove and avoid malware (read October 7, 2026)
- Microsoft Learn: Microsoft Defender Offline (read October 7, 2026)
- Microsoft Learn: How Microsoft names malware (read October 7, 2026)