Critroni Ransomware: what it is and how to remove it
Critroni is a very dangerous ransomware that can easily infect your computer, encrypt your files and try to swindle money from you in exchange for the decryption key. This ransomware is relatively new, so there is no surprise that there isn't much information about it.
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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Critroni Ransomware: summary
| Detection names | No Microsoft detection name is known |
|---|---|
| Ransom note | A message left on the computer; the text is quoted in full below |
| 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 | Critroni Ransomware |
| Type | File-encrypting ransomware |
| Symptoms | An unknown program in Installed apps and a ransom note left in folders |
| Evidence | One write-up by a security site; no sample analysed yet |
| Free decryptor | No free decryptor is known (checked 7 October 2026) |
| First seen | 25 February 2021 |
| Facts checked | 7 October 2026 |
Names and addresses to look for
- Note file:
the ransom note
How Critroni Ransomware behaves
From our report of Feb 2021 · not reviewed since
Critroni virus is the ransomware scaring victims into paying
Critroni is a very dangerous ransomware that can easily infect your computer, encrypt your files and try to swindle money from you in exchange for the decryption key.
This ransomware is relatively new, so there is no surprise that there isn't much information about it. However, it looks like this ransomware works very similarly to well-known viruses that are called Cryptolocker and Cryptowall.
In fact, Critroni ransomware virus can be called a copy of these threats. If this malicious intruder infiltrates the computer, it scans the system for specific files and then encrypts them. After that, you will discover that these files are blocked and that you can't open them. Instead of that, this threat will show you a step-by-step guide on what you should do in order to recover your encrypted files.
This guide is very precise and even explains how to download Tor, how to pay the ransom using Bitcoins, and gives similar instructions. Please be very careful with this threat and think twice whether it is worth making this payment or not because hackers might fail to unblock your files after getting your payment.
In addition, for recovering the connection to your files, you should try using for system damage.
What is the main thing showing that your computer has already been affected Critroni? It's this warning message that shows up after trying to open any of your important files.
From our report of Feb 2021 · not reviewed since
Infectious files spread via email
Normally, such viruses as ransomware, trojans, malware, and rogues travel around with a help of spam.
In most cases, such misleading emails claim that the user needs to update the attachment and check what is said in it.
Nevertheless, at the moment of writing, Critroni ransomware is also actively spread using fake alerts offering free updates. In most cases, people are offered to update their Java, Flash Player, FLV Player, web browser, or similar programs. We have noticed lots of fake alerts spreading around at this moment, so you should be very careful with them.
The safest way to deal with them is to close them. You may also need to leave a website that shows it for you. Otherwise, you can easily download Critroni to your computer.
What is more, it looks like cybercriminals, who are responsible for releasing Critroni ransomware, are trying to sell their dubious creation on the black market. So, it is possible that this ransomware may become very popular among scammers and cybercriminals.
To sum up, Critroni virus is one of the most dangerous ransomware that is spread around at this moment. It is very hard to remove this ransomware from the system and it's even much harder to recover the encrypted files. In order to remove this malicious infection, you should rely on a reliable and updated anti-spyware program.
Fortunately, there are several programs that can be used for decrypting encrypted files. For avoiding this threat, please be careful with unsafe websites, avoid opening suspicious email attachments, and avoid downloading unfamiliar programs.
The Critroni Ransomware note
Your personal files are encrypted
Your documents, photos, databases and other important files have been encrypted with strongest encryption and unique key, generated for this computer.
Private decryption key is stored on a secret Internet server and nobody can decrypt your files until you pay and obtain the private key.
You only have 72 hours to submit the payment. If you do not send money within provided time, all your files will be permanently crypted and no one will be able to recover them.
Press 'View' to view the list of files that have been encrypted.
Press 'Next' to connect to the secret server and follow instructions.
How to remove Critroni 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 Critroni 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 Critroni 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 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 Critroni Ransomware, 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 Critroni 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 Critroni 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.
Repair damaged system components
Once a computer is infected with malware, its system is changed to operate differently. For example, an infection can alter the Windows registry database, damage vital bootup and other sections, delete or corrupt DLL files, etc. Once a system file is damaged by malware, antivirus software is not capable of doing anything about it, leaving it just the way it is. Consequently, users might experience performance, stability, and usability issues, to the point where a full Windows reinstall is required.
Therefore, we highly recommend using a one-of-a-kind, patented technology of repair. Not only can it fix virus damage after the infection, but it is also capable of removing malware that has already broken into the system thanks to several engines used by the program. Besides, the application is also capable of fixing various Windows-related issues that are not caused by malware infections, for example, Blue Screen errors, freezes, registry errors, damaged DLLs, etc.
- Download the application by clicking on the link above
- Click on the ReimageRepair.exe
- If User Account Control (UAC) shows up, select Yes
- Press Install and wait till the program finishes the installation process
- The analysis of your machine will begin immediately
- Once complete, check the results - they will be listed in the Summary
- You can now click on each of the issues and fix them manually
- If you see many problems that you find difficult to fix, we recommend you purchase the license and fix them automatically.
By employing , you would not have to worry about future computer issues, as most of them could be fixed quickly by performing a full system scan at any time. Most importantly, you could avoid the tedious process of Windows reinstallation in case things go very wrong due to one reason or another.
Identify ransomware affecting your PC
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.
Important steps to take before you begin malware removal
File encryption is one component of a ransomware infection, which may also include credential theft, persistence mechanisms, and lateral movement. However, it is important to understand that malware may perform various changes within a Windows operating system, including persistence, scheduled tasks, registry modifications, and security feature tampering.
IMPORTANT for those without backups! →
If you attempt to use security or recovery software immediately, you might permanently damage your files, and even a working decryptor then would not be able to save them.
Before you proceed with the removal instructions below, you should copy the encrypted files onto a separate medium, such as USB flash drive or SSD, and then disconnect them from your computer. The storage device should remain disconnected after copying to prevent accidental modification or deletion. Encrypted data itself does not contain active malicious code, but only the encrypted files—not executables or scripts—should be transferred.
The instructions below might initially seem overwhelming and complicated, but they are not difficult to understand as long as you follow each step in the appropriate order. This comprehensive free guide will help you to handle the malware removal and data recovery process correctly.
If you have any questions, comments, or are having troubles with following the instructions, please do not hesitate to contact us via the Ask Us section.
IMPORTANT! →
It is vital to eliminate malware infection from the computer fully before starting the data recovery process, otherwise ransomware might re-encrypt retrieved files from backups repeatedly.
Restore files using data recovery software
Since many users do not prepare proper data backups prior to being attacked by ransomware, they might often lose access to their files permanently. Paying criminals is also very risky, as they might not fulfill the promises and never send back the required decryption tool.
While this might sound terrible, not all is lost - data recovery software might be able to help you in some situations (it highly depends on the encryption algorithm used, whether ransomware managed to complete the programmed tasks, etc.). Since there are thousands of different ransomware strains, it is immediately impossible to tell whether third-party software will work for you.
Therefore, we suggest trying regardless of which ransomware attacked your computer. Before you begin, several pointers are important while dealing with this situation:
- Since the encrypted data on your computer might permanently be damaged by security or data recovery software, you should first make backups of it - use a USB flash drive or another storage.
- Only attempt to recover your files using this method after you perform a scan with anti-malware software.
Install data recovery software
- Download .
- Double-click the installer to launch it.
- Follow on-screen instructions to install the software.
- As soon as you press Finish, you can use the app.
- Select Everything or pick individual folders where you want the files to be recovered from.
- Press Next.
- At the bottom, enable Deep scan and pick which Disks you want to be scanned.
- Press Scan and wait till it is complete.
- You can now pick which folders/files to recover - don't forget you also have the option to search by the file name!
- Press Recover to retrieve your files.
Scan your system with anti-malware
If you are a victim of ransomware, you should employ anti-malware software for its removal. Some ransomware can self-destruct after the file encryption process is finished. Even in such cases, malware might leave various data-stealing modules or could operate in conjunction with other malicious programs on your device.
or can detect and eliminate all ransomware-related files, additional modules, along with other viruses that could be hiding on your system. The security software is really easy to use and does not require any prior IT knowledge to succeed in the malware removal process.
Isolate the infected computer
Some ransomware strains aim to infect not only one computer but hijack the entire network. As soon as one of the machines is infected, malware can spread via the network and encrypt files everywhere else, including Network Attached Storage (NAS) devices. NAS devices are commonly compromised via reused administrator credentials and remote access services, and attackers may also delete existing snapshots. If your computer is connected to a network, it is important to isolate it to prevent re-infection after ransomware removal is complete.
In modern environments, ransomware often spreads using stolen credentials, remote management tools, VPN connections, and cloud synchronization services, not only through shared network drives.
The easiest way to disconnect a PC from everything is simply to plug out the ethernet cable. This does not disconnect wireless networks, VPN connections, or cloud services, which must also be disabled separately. However, in the corporate environment, this might be extremely difficult to do (also would take a long time). In many organizations, devices are centrally managed, and network isolation is typically performed by IT or security teams using endpoint security or device management tools. The method below will disconnect from all the networks, including local and the internet, isolating each of the machines involved.
On modern Windows systems, network connections can also be disabled through the Settings app or automatically isolated using endpoint detection and response (EDR) tools.
- Type in Control Panel in Windows search and press Enter
- Go to Network and Internet
- Click Network and Sharing Center
- On the left, pick Change adapter settings
- Right-click on your connection (for example, Ethernet), and select Disable
- Confirm with Yes.
If you are using some type of cloud storage you are connected to, you should disconnect from it immediately. It is also advisable to disconnect all the external devices, such as USB flash sticks, external HDDs, etc. Once the malware elimination process is finished, you can connect your computers to the network and internet, as explained above, but by pressing Enable instead. Before reconnecting, credentials should be reset, persistence mechanisms checked, and backups verified to ensure reinfection does not occur.
From our report of Feb 2021 · not reviewed since
How to remove Critroni Ransomware from my computer?
Usually, users can restore their files from the system backup or using file recovery tools.
If you have been performing backups, you should be capable of restoring your files after the Citroni ransomware removal. In addition, for that, you can also try such programs as R-Studio or Photorec.
Of course, you shouldn't forget that you must remove Critroni ransomware files from the system. You can do that by running a full system scan with any of these applications: , , or another reputable anti-spyware program. Then it is possible to recover your data.
We highly recommend thinking about the prevention of such infections as Cintroni ransomware virus. What is more, it is also recommended to store your most valuable files in an online storing place or use a safe USB/external HDD/CD or DVD.
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 critroni Ransomware 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.
Do not let government spy on you
The government has many issues in regards to tracking users' data and spying on citizens, so you should take this into consideration and learn more about shady information gathering practices.
Avoid any unwanted government tracking or spying by going totally anonymous on the internet.
You can choose a different location when you go online and access any material you want without particular content restrictions. You can easily enjoy internet connection without any risks of being hacked by using VPN.
Control the information that can be accessed by government any other unwanted party and surf online without being spied on. Even if you are not involved in illegal activities or trust your selection of services, platforms, be suspicious for your own security and take precautionary measures by using the VPN service.
Backup files for the later use, in case of the malware attack
Computer users can suffer from data losses due to cyber infections or their own faulty doings.
Ransomware can encrypt and hold files hostage, while unforeseen power cuts might cause a loss of important documents. If you have proper up-to-date backups, you can easily recover after such an incident and get back to work. It is also equally important to update backups on a regular basis so that the newest information remains intact - you can set this process to be performed automatically.
When you have the previous version of every important document or project you can avoid frustration and breakdowns. It comes in handy when malware strikes out of nowhere. Use for the data restoration process.
Questions about Critroni Ransomware
Is there a free Critroni Ransomware decryptor?
We last checked on 7 October 2026, and for Critroni 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 "Critroni 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.
Did Critroni Ransomware steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by Critroni Ransomware, but the only confirmed sign is critroni Ransomware 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.
How did Critroni Ransomware get on my computer?
The way Critroni 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 critroni Ransomware 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.
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.
Is Critroni 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 the ransom note?
Reading it is fine if you open it in Notepad. A plain text the ransom note 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.
How do I open my .docx, .jpg and other files locked by Critroni?
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 Critroni 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.
Will Fortect remove Critroni 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 Critroni 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
- 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)