2021 ransomware: what it is and how to remove it
2021 ransomware is a computer infection that encrypts files on an affected device, renames them, and creates ransom notes that demand to purchase necessary decryption tools. This cryptovirus belongs to the pervasive Dharma ransomware family that has been first detected in 2016.
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.
Automatic
Get a free scan and check if your PC is infected.
Fortect finds malware, unwanted programs and the Windows damage they leave behind, and repairs it in one pass.
Before you restore backups, a full scan can confirm the program that added .2021 is gone.
Do it yourself · free Remove 2021 ransomware yourself 6 steps, about 18 minutes, no software needed.
Start the steps
2021 ransomware: summary
| Distribution | Spam emails, file-sharing platforms, malicious websites, etc. |
|---|---|
| name | 2021 ransomware |
| type | File locking virus, crypto-malware |
| family | Dharma |
| appended file extension | .id-(appointed user ID).[decrypt2021@aol.com].2021 |
| Ransom note | FILES ENCRYPTED.txt and info.hta |
| 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
| Criminal contact info | decrypt2021@aol.com and decrypt21@aol.com |
|---|---|
| Virus removal | Trustworthy anti-malware software should be used to eliminate all computer infections and protect it from such incidents |
| Detection names | No Microsoft detection name is known |
| Encrypted file extension | .2021 |
| Decryptor | No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates |
| Damage | Not recorded in the old report |
| Name | 2021 ransomware |
| Type | File-encrypting ransomware |
| Symptoms | Files renamed with a new extension and a ransom note left in folders |
| Evidence | 4 write-ups by security sites; no sample analysed yet |
| Encrypted files | .2021 |
| Attacker contacts | decrypt2021@aol.com |
| Free decryptor | No free decryptor is known (checked 6 October 2026) |
| First seen | 6 January 2021 |
| Facts checked | 6 October 2026 |
- File extension:
.2021 - Note file:
info.hta - Contact:
decrypt2021@aol.com
From our report of Jan 2021 · not reviewed since
More from our earlier report on 2021 ransomware
- If users want their computer to run as usual, they should use the system repair tools to fix any damage the cryptovirus has done to system files/settings
- All your files have been encrypted!
- All your files have been encrypted due to a security problem with your PC.
- If you want to restore them, write us to the e-mail decrypt2021@aol.com Write this ID in the title of your message - In case of no answer in 24 hours write us to theese e-mails:decrypt21@aol.com You have to pay for decryption in Bitcoins.
- The price depends on how fast you write to us.
- After payment we will send you the decryption tool that will decrypt all your files.
- Free decryption as guarantee Before paying you can send us up to 1 file for free decryption.
- The total size of files must be less than 1Mb (non archived), and files should not contain valuable information.
- (databases,backups, large excel sheets, etc.)
- How to obtain Bitcoins The easiest way to buy bitcoins is LocalBitcoins site.
How 2021 ransomware behaves
From our report of Jan 2021 · not reviewed since
2021 ransomware – a file-locking parasite that blackmails its victims through FILES ENCRYPTED.txt ransom note
2021 ransomware is a computer infection that encrypts files on an affected device, renames them, and creates ransom notes that demand to purchase necessary decryption tools.
This cryptovirus belongs to the pervasive Dharma ransomware family that has been first detected in 2016.
Immediately after gaining access to a computer, 2021 virus scans the most frequently used files and starts encrypting them. During this process, all personal victim files, such as documents, videos, archives, databases, are renamed by adding .id-(appointed user ID).[decrypt2021@aol.com].2021 extension.
To explain what has happened to victim devices and forward instruction on what to do next, .2021 file virus generates ransom notes - a pop-up window info.hta and text file FILES ENCRYPTED.txt. The purpose of these notes is to force users to contact the criminals by given emails - decrypt2021@aol.com and/or decrypt21@aol.com.
The ransomware family of .2021 extension virus is introducing new versions each week. They're mostly spread through spam emails, file-sharing platforms, and malicious websites. Files encrypted by older versions can be decrypted, although victims of new variants must wait for the good guys to create the necessary tools. Examples of the latest versions:
Ransom notes of 2021 ransomware are practically identical to its previous version. Text file note is short and contains mainly two email addresses to establish contact with the cybercriminals:
While the message in the pop-up window is a bit more instructive - provides a victim ID, free decryption of 1 file guarantee, same two emails, and instructions on how to acquire Bitcoins as the ransom will have to be forwarded using that cryptocurrency (the decryption toolkit price isn't specified):
Victims of ransomware attacks should never trust their developers and send them the money for various reasons. First of all, as soon as the criminals get paid, they might disappear. Second - they might ask for more money.
Third - instead of the deciphering tool, more malware could be sent. And last but not least - the sent decryption tool might not work, so victims lose not only their files but their hard-earned money too.
If kept updated, these trustworthy apps could prevent malware infections in the future.
Manual 2021 ransomware removal options are listed at the bottom of this article, but they're recommended only for tech-savvy computer users. Following threat elimination, users are urged to perform system repair with the powerful system tune-up tool in order to fix any modifications the cryptovirus might have caused to system settings/files.
- Bip
- 4help
- Kobos
From our report of Jan 2021 · not reviewed since
File-sharing platforms – a hotbed of malicious software
Various file-sharing platforms, especially popular torrent sites, have become a perfect nesting space for different kinds of malware due to the fact that no security protocols are controlling who uploads what onto them. And the cybercriminals love to exploit that.
They name their creations by something that will lure the unaware user, like an illegal software activation kit (aka crack) for the latest game, or expensive pirated software, or anything alike, and upload it. And that's it, now they wait until someone downloads the torrent along with the virus payload file.
To evade infections by various malware, users should do many steps, but one of the most important is to scan every incoming file with a reliable anti-malware tool. One more suggestion from us - don't download anything from torrent sites and other file-sharing platforms.
The 2021 ransomware note
all your data has been locked us
You want to return?
Write email decrypt2021@aol.com or decrypt21@aol.com
How to remove 2021 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 2021 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
2021 ransomware encrypts everything it can reach, including drives and shares you connect later. Cut the network first: cable out, or Wi-Fi off from the taskbar.
Then unplug every USB stick and backup disk and pause cloud sync, so the encrypted versions do not replace your online copies. Do not reconnect any of them until the ransomware is removed from the Windows 11 or Windows 10 PC.
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
Copy
info.htaand one or two files ending in.2021to a USB stick, and leave the originals where they are.From another device, upload the note and a sample file to ID Ransomware or No More Ransom's Crypto Sheriff, which name the family from the note, the extension and the file structure.
Write down the contact address and your personal ID from the note, because a decryptor or the police may ask for them.
Warning: Never contact the attackers from the infected Windows 11 or Windows 10 PC.
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
For 2021 ransomware, no free decryptor is known (checked 6 October 2026). Search the family name in the No More Ransom decryption tools list and in the free decryptors of Emsisoft, Avast and Kaspersky, because new tools appear years after an attack.
Important: Keep the encrypted files even if nothing works today, and do not pay before every free option is ruled out: payment does not guarantee a working key.
Decryptors run on Windows 11 and Windows 10, but only after the ransomware itself is removed.
Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 4: Remove the ransomware before you restore or decrypt
Restoring or decrypting files while 2021 ransomware still runs lets it encrypt them again. Run a Full scan in Windows Security > Virus & threat protection > Scan options, then the Microsoft Defender Antivirus (offline scan).
If the ransomware blocks Windows Security, start Safe Mode with Networking and scan from there. Some families install a password stealer as well, so let both scans finish on Windows 11 or 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
Open Command Prompt as administrator and run
vssadmin list shadows. If it lists copies dated before the attack, right-click a folder with encrypted files in File Explorer, choose Properties > Previous Versions, and open or restore a version from before that date.ShadowExplorer, a free tool, shows the same copies when the tab is empty or hidden. Most current families delete shadow copies, so an empty list is normal, but the check takes two minutes on Windows 11 or Windows 10.
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
Restore from an external backup, File History or OneDrive's version history, choosing a date before the attack. Connect the backup drive only after the scans are clean, or the ransomware encrypts it too.
If there is no backup, file recovery software can sometimes find the deleted originals, because some ransomware writes an encrypted copy and deletes the original file.
Stop writing to the drive and try recovery on Windows 11 or Windows 10 before new files overwrite the space.
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 Jan 2021 · not reviewed since
Instructions for 2021 ransomware removal with anti-malware software
As we've stated in the first chapter of this article, paying the ransom might lead to a lose-lose situation where not only the encrypted files would be lost but money too. So don't doubt for a second and remove 2021 ransomware from infected devices ASAP.
Although some computer infections could be removed manually, it is not advised for less experienced users because it's not that easy. It's better to leave such tasks to professionals.
File-locking viruses tend to corrupt computers host files and Windows Registry. That's why experts recommend using reliable system repair tools such as the app to restore any modifications the computer infection might have implemented.
[GI=method-1]Safe Mode with Networking can be useful to eliminate viruses if they can't be removed when Windows in normal mode
[GI=method-2]System Restore function might be helpful to get rid of the computer infection
This app might be able to recover encrypted files.
Recover previous files version with Windows Previous Version feature
With this feature, users might restore files one at a time.
Recover .2021 extension files by using Shadow Explorer
If Shadow Volume Copies weren't removed by the cryptovirus when it was encrypting files, then Shadow Explorer might be a helpful data recovery tool.
No decryption tool is currently available
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.
Make the next attack harmless
2021 ransomware could only hurt the files that had no second copy, and the signs (files that end in .2021 and no longer open) showed exactly which ones those were.
The 3-2-1 rule fixes that:
- three copies
- two media
- one disconnected
A practical version for a home PC: OneDrive or another cloud backup with version history, plus an external disk that you plug in once a week for File History and then unplug. Test a restore now and then by opening a few files from the backup on another device.
Details, schedules and what not to back up are in our 3-2-1 backup guide for Windows.
Choose a proper web browser and improve your safety with a VPN tool
Online spying has got momentum in recent years and people are getting more and more interested in how to protect their privacy online.
One of the basic means to add a layer of security - choose the most private and secure web browser. Although web browsers can't grant full privacy protection and security, some of them are much better at sandboxing, HTTPS upgrading, active content blocking, tracking blocking, phishing protection, and similar privacy-oriented features.
However, if you want true anonymity, we suggest you employ a powerful VPN - it can encrypt all the traffic that comes and goes out of your computer, preventing tracking completely.
Lost your files? Use data recovery software
While some files located on any computer are replaceable or useless, others can be extremely valuable.
Family photos, work documents, school projects - these are types of files that we don't want to lose. Unfortunately, there are many ways how unexpected data loss can occur:
- power cuts
- Blue Screen of Death errors
- hardware failures
- crypto-malware attack
- even accidental deletion
To ensure that all the files remain intact, you should prepare regular data backups. You can choose cloud-based or physical copies you could restore from later in case of a disaster. If your backups were lost as well or you never bothered to prepare any, can be your only hope to retrieve your invaluable files.
Questions about 2021 ransomware
How do I open .2021 files?
You cannot open them by renaming or with another program, because the content of files ending in .2021 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.
Should I pay the ransom in info.hta?
Not before you have tried everything else. Identify the family from info.hta 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.
Can a data-recovery company decrypt my files for a fee?
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.
Is there a free 2021 ransomware decryptor?
We last checked on 6 October 2026, and for 2021 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 "2021 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.
How did 2021 ransomware get on my computer?
The way 2021 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 .2021 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.
Did 2021 ransomware steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by 2021 ransomware, but the only confirmed sign is files that end in .2021 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 2021 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.
What does info.hta tell me about the ransomware?
Quite a lot. The file name info.hta, 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.
My files got .2021 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 .2021 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 2021 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 2021 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
- Uscybersecurity: 8 Different Types of Malware (read October 6, 2026)
- Semvirus: Semvirus (read October 6, 2026)
- CISA: StopRansomware (read October 6, 2026)
- No More Ransom (read October 6, 2026)
- FTC: How to recognize, remove and avoid malware (read October 6, 2026)