CARLOS ransomware: what it is and how to remove it
CARLOS ransomware, found by S!Ri in the first half of February, is a complex computer virus that is in the search for encryptable files. The malware developers are seeking to collect monetary income from their victims.
Facts checked October 6, 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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CARLOS ransomware: summary
| Name | CARLOS ransomware |
|---|---|
| Type | Ransomware/malware |
| Discoverer | S!Ri |
| Extension | This ransomware virus appends a long extension that contains three parts: a random mix of 7 symbols that are letters and numbers, crooks' email address, and the appendix – .CARLOS |
| Ransom note | The ransomware message provides a text note written in a Notepad blank that is named readme-warning.txt. Here crooks introduce the victims to what has just happened and provide the users with a demand to pay some type of price for receiving decryption software |
| Criminals' email | Crooks include the carlosrestore2020@aol.com email address into the ransom message as a way to make contact |
| 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 15 more facts
| Spreading | The ransomware-related payload can get distributed through email spam messages and their malicious attachments, software cracks, exploited OS flaws, vulnerable RDP configuration, etc. |
|---|---|
| Data recovery | If you are looking for a way to recover your locked files, you should go to the end of this article and take a look at all of the possibilities that are written there |
| Detection names | No Microsoft detection name is known |
| Contact | carlosrestore2020@aol.com |
| Encrypted file extension | .carlos |
| Decryptor | No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates |
| Distribution | Not recorded in the old report |
| Damage | Not recorded in the old report |
| Symptoms | Files renamed with a new extension and a ransom note left in folders |
| Evidence | 5 write-ups by security sites; no sample analysed yet |
| Encrypted files | .carlos |
| Attacker contacts | carlosrestore2020@aol.com |
| Free decryptor | No free decryptor is known (checked 6 October 2026) |
| First seen | 7 February 2020 |
| Facts checked | 6 October 2026 |
- File extension:
.carlos - Note file:
readme-warning.txt - Contact:
carlosrestore2020@aol.com
From our report of Feb 2020 · not reviewed since
More from our earlier report on CARLOS ransomware
- You should get rid of the parasite as soon as you spot the first symptoms of infection.
- Perform the removal with the help of a trustworthy antimalware program
- If you have discovered any damage in your computer system, try performing a fixing process with the help of
How CARLOS ransomware behaves
From our report of Feb 2020 · not reviewed since
CARLOS ransomware is a damaging cyber threat existing in the cybersphere since the start of February 2020
CARLOS ransomware, found by S!Ri in the first half of February, is a complex computer virus that is in the search for encryptable files.
The malware developers are seeking to collect monetary income from their victims. First of all, the ransomware virus employs a symmetric or asymmetric encryption cipher and runs it on all components found. This can include images, word documents, audio, video, and other files.
When the encryption is finished, CARLOS ransomware drops a ransom note named readme-warning.txt that is written in a Notepad blank. The users are introduced to what has just happened and how to deal with it.
Crooks state that they absolutely do not care about the users (that is true) because it is only a business and they will get their decrypted files back after the payment anyway (not always true). However, CARLOS ransomware developers try to provide some type of evidence of the existing decryption software by allowing the victims to send 2 files that include simple extensions such as .jpg, .xls, or .doc.
For cooperation, these people include the carlosrestore2020@aol.com email address where both parties have to talk about the conditions of the payment. Afterward, crooks claim that they will deliver detailed instructions on how to use the decryption software.
Once all of the existing files and documents are locked by CARLOS ransomware it appends an extension that is completed from three parts to all the filenames of encrypted data.
The malware appends a random mix of 7 symbols that can be letters or numbers, crooks' given email address, and the extension - .CARLOS. For example, if you had a file that was named database.xls, after the encryption, it would turn to database.xls. .[carlosrestore2020@aol.com].CARLOS.
CARLOS virus is categorized as dangerous and complex malware as it can make a person completely use his files and experience other harmful malware infiltration. Email spam campaigns, cracked software, exploiting OS flaws, and vulnerable RDP configuration create the best conditions for this cyber threat to spread.
The potential victims can receive the malicious payload looking like a legitimate file at first and notice that something is wrong just when it is too late.
CARLOS ransomware aims to alter the Windows Registry by adding suspicious keys into it that allow the malware to bring on its malicious module. Also, it performs changes on the Windows Task Manager by injecting malicious processes in order to launch its payload too. Sometimes the included executables might not create any concern as they can come looking as completely normal components of some type of legitimate software.
Furthermore, CARLOS ransomware might disable antivirus programs once it settles on the Windows PC. If this happens, some tools might not be able to detect or remove the malicious software.
However, according to VirusTotal, 45 AV engines do spot this malware and provide it as suspicious, malicious, malware, trojan, or ransomware. These types of results are kind of good considering the fact that 45 is out of the total 71 which is more than half.
Additionally, CARLOS ransomware will ensure that its module is launched every time when the computer is booted. This can include scanning the system for encryptable documents once in a while. The threat uses unique encryption keys to lock up all the files that are found on the computer. Afterward, criminals store both encryption and decryption tools on remote servers that are accessible only for their owners.
The ransom note that is provided by CARLOS ransomware will also try to convince you to pay the ransom price. Even though there are no particular demands provided in that message, criminals can ask anywhere from $50 to $2000 or even more if they are very greedy.
However, in most of the cases, they urge for Bitcoin or another type of cryptocurrency for the payment to stay anonymous. Here, take a look at the full ransom message:
A piece of advice would be to stay away from contacting CARLOS ransomware developers. As these people already mentioned, they do not care about the victims as they are orientated toward their own business.
When you proceed with the payment and it reaches the crooks, you can get scammed. Simply, hackers might provide you with a fake tool or just take the money and leave you with no decryption software at all.
It might be hard to understand that your files can get permanently lost, but there are always some alternatives that you can try. First, focus on CARLOS ransomware removal that you need to complete as soon as you see encrypted files and the provided ransom note.
However, if you are having trouble with the elimination or if the virus is blocking your anti-spyware program, you should run your machine in Safe Mode with Networking or activate the System Restore feature that could help you to fix things.
When you successfully remove CARLOS ransomware from your Windows computer and the malware is no longer causing any problems, go to the end of this article and there you will find some data recovery tips.
Beware that CARLOS ransomware might have deleted your Shadow Volume Copies of the encrypted software, so a particular tool that requires the Shadow Copies to remain safe might not work. Also, if the virus managed to damage your Windows hosts file in order to prevent you from visiting security-related sources, you should delete this file while eliminating the ransomware virus, otherwise, the access will remain blocked.
From our report of Feb 2020 · not reviewed since
Exploited OS vulnerabilities distribute ransomware
This ransomware can have different types of distribution sources.
However, experts have discovered that the ransomware virus is widely distributed by misusing operating system flaws. This includes products such as Microsoft Office, web browsers, the operating system itself, and other third-party applications.
Furthermore, crooks' can pretend to be from reliable shipping companies and decide to spam you with fake order delivery or shipping information notifications. It can look like the message is coming from a reputable source but it truly is not. Do not open any attached files or documents before scanning them with antimalware software. In addition, ransomware can get distributed through other sources such as:
According to cybersecurity experts from Virusai.lt, all computer systems need to include reliable antimalware protection. The more the security features the anti-spyware has, the better it is for the device. Also, do not forget to update the product regularly, otherwise, it cannot be able to operate properly and might include flaws.
- Cracked software. These products appear on p2p networks such as The Pirate Bay, eMule, and BitTorrent.
- Vulnerable RDP. If the configuration does not include a reliable password or includes none security codes at all, the hackers can easily access the port.
- Malvertising ads. If you are a frequent visitor of third-party networks and like clicking on various advertisements, there is a risk to get infected with malware.
The CARLOS ransomware note
::: Greetings :::
Little FAQ:
.1.
Q: Whats Happen?
A: Your files have been encrypted and now have the "CARLOS" extension. The file structure was not damaged, we did everything possible so that this could not happen.
.2.
Q: How to recover files?
A: If you wish to decrypt your files you will need to pay in bitcoins.
.3.
Q: What about guarantees?
A: Its just a business. We absolutely do not care about you and your deals, except getting benefits. If we do not do our work and liabilities - nobody will cooperate with us. Its not in our interests.
To check the ability of returning files, you can send to us any 2 files with SIMPLE extensions(jpg,xls,doc, etc... not databases!) and low sizes(max 1 mb), we will decrypt them and send back to you. That is our guarantee.
.4.
Q: How to contact with you?
A: You can write us to our mailbox: carlosrestore2020@aol.com
.5.
Q: How will the decryption process proceed after payment?
A: After payment we will send to you our scanner-decoder program and detailed instructions for use. With this program you will be able to decrypt all your encrypted files.
.6.
Q: If I don't want to pay bad people like you?
A: If you will not cooperate with our service - for us, its does not matter. But you will lose your time and data, cause only we have the private key. In practice - time is much more valuable than money.
:::BEWARE:::
DON'T try to change encrypted files by yourself!
If you will try to use any third party software for restoring your data or antivirus solutions - please make a backup for all encrypted files!
Any changes in encrypted files may entail damage of the private key and, as result, the loss all data.
How to remove CARLOS 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 CARLOS ransomware 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 CARLOS ransomware 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 confirm the family
Your files now end in
.carlosand the instructions are inreadme-warning.txt. Save both to a USB stick, a copy of the note and two small encrypted files, before anything else.On another device, check them with ID Ransomware or Crypto Sheriff: the family name decides which decryptor, if any, can help. Keep the note's ID and contact line for your report.
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 CARLOS ransomware, no free decryptor is known (checked 6 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 CARLOS ransomware 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 CARLOS ransomware 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 Feb 2020 · not reviewed since
CARLOS ransomware deletion steps and data recovery alternatives
We have introduced you to all the unwanted effects that ransomware infections can bring, and now it is time for you to get rid of the cyber threat before more damage appears. You should remove CARLOS ransomware with the help of anti-spyware software and avoid trying manual steps because this type of process can relate in making dangerous mistakes.
If you are having trouble with CARLOS ransomware removal, try booting your computer in Safe Mode with Networking or activating the System Restore feature to diminish all malicious activities. If you discover any altered components, try repairing them with .
[GI=method-1]To deactivate malicious changes on your Windows computer and bring the system back to normal, you should boot the machine in Safe Mode with Networking like shown in the following instructions.
[GI=method-2]To diminish all malware-laden activities and deactivate the ransomware virus itself, you should reboot your device via System Restore. The below-provided steps should help you succeed in such a task.
If the ransomware virus has locked your files and documents, you can try restoring them with this piece of software.
Windows Previous Versions feature might allow you to recover some files.
If you have booted the computer in System Restore in the past, this method might help you to bring some files back.
Shadow Explorer software might work for your files.
If the ransomware virus did not permanently destroy or erase the Shadow Volume Copies of your encrypted files, try using this technique for the recovery process.
The .CARLOS files decrypter is not available yet.
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 files that end in .carlos and no longer open; 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.
Protect your privacy - employ a VPN
There are several ways how to make your online time more private - you can access an incognito tab.
However, there is no secret that even in this mode, you are tracked for advertising purposes. There is a way to add an extra layer of protection and create a completely anonymous web browsing practice with the help of VPN. This software reroutes traffic through different servers, thus leaving your IP address and geolocation in disguise.
Besides, it is based on a strict no-log policy, meaning that no data will be recorded, leaked, and available for both first and third parties. The combination of a secure web browser and VPN will let you browse the Internet without a feeling of being spied or targeted by criminals.
No backups? No problem. Use a data recovery tool
If you wonder how data loss can occur, you should not look any further for answers - human errors, malware attacks, hardware failures, power cuts, natural disasters, or even simple negligence.
In some cases, lost files are extremely important, and many straight out panic when such an unfortunate course of events happen. Due to this, you should always ensure that you prepare proper data backups on a regular basis.
If you were caught by surprise and did not have any backups to restore your files from, not everything is lost. is one of the leading file recovery solutions you can find on the market - it is likely to restore even lost emails or data located on an external device.
Questions about CARLOS ransomware
How do I open .carlos files?
You cannot open them by renaming or with another program, because the content of files ending in .carlos has been encrypted. The only ways back are a working decryptor for the family, or clean copies from elsewhere:
- OneDrive versions
- File History
- an offline backup drive
- Previous Versions if the ransomware did not delete them
Identify the family first by uploading the ransom note and one encrypted file to ID Ransomware or No More Ransom. Avoid websites and programs that promise to open any encrypted file; they do not work and some are scams.
Is there a free CARLOS ransomware decryptor?
We last checked on 6 October 2026, and for CARLOS ransomware 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 "CARLOS ransomware 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.
How did CARLOS ransomware get on my computer?
The way CARLOS ransomware 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 files that end in .carlos and no longer open, and check the Downloads folder and Installed apps sorted by date. Keep anything suspicious for your report, but do not run it again.
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.
Did CARLOS ransomware steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by CARLOS ransomware, but the only confirmed sign is files that end in .carlos and no longer open, 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 CARLOS ransomware 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.
Should I open readme-warning.txt?
Reading it is fine if you open it in Notepad. A plain text readme-warning.txt cannot harm the PC. Be careful with notes in HTA or HTML format: double-clicking those runs them in a window that can contain scripts, so right-click and choose Open with > Notepad instead.
The note tells you the contact addresses, the claimed amount and the deadline. Do not visit links or write to the addresses from this PC. Use the note to identify the family and check for a free decryptor first.
My files got .carlos overnight. What happened?
Ransomware often runs at night or when the PC is idle, so the encryption finishes before anyone notices. It usually entered earlier through a cracked program, a fake installer, an e-mail attachment or remote desktop with a weak password.
The .carlos extension marks every file it reached. Start by disconnecting the PC from the network, then identify the family from the ransom note and one encrypted file, check for a decryptor, and look for copies in backups and OneDrive before you consider anything else.
Will Fortect remove CARLOS ransomware?
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 CARLOS ransomware, 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
- Twitter: .CARLOS #ransomware (read October 6, 2026)
- Virus Total: 45 engines detected this file (read October 6, 2026)
- Wikipedia: Remote Desktop Protocol (read October 6, 2026)
- Virusai: Virusai.lt (read October 6, 2026)
- CISA: StopRansomware (read October 6, 2026)