KillSwitch ransomware virus: what it is and how to remove it
KillSwitch virus is a hazardous ransomware created by someone who was probably inspired by the methods used by WannaCry ransomware. The authors of the ransomware named the executive file as CryptoKill.exe, probably to confuse the victims and make them search for information about CryptoKill virus online.
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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KillSwitch ransomware virus: summary
| Detection names | No Microsoft detection name is known |
|---|---|
| Ransom note | Not recorded in our earlier report |
| Contact | Not recorded in our earlier report |
| Encrypted file extension | .switch |
| 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 9 more facts
| Damage | Not recorded in the old report |
|---|---|
| Name | KillSwitch ransomware virus |
| Type | File-encrypting ransomware |
| Symptoms | Files renamed with a new extension |
| Evidence | 3 write-ups by security sites; details still limited |
| Encrypted files | .switch |
| Free decryptor | No free decryptor is known (checked 6 October 2026) |
| First seen | 2 June 2017 |
| Facts checked | 6 October 2026 |
- File extension:
.switch
From our report of Jun 2017 · not reviewed since
More from our earlier report on KillSwitch ransomware virus
- Your files has been encrypted by KillSwitch KillSwitch is a new kind of cryptography malware, unlike the most of other ones utilizing encryption like ransomware… All of your files are encrypted with AES-256 ciphers.
- Unlocking of your files is not possible because KillSwitch generates unique one-way encryption keys without keys used to decrypt.
- Your only option would be to attempt to break the encryption, but this is very hard since AES246 is a strong cipher algorithm.
How KillSwitch ransomware virus behaves
From our report of Jun 2017 · not reviewed since
KillSwitch ransomware has no killswitch and is in development mode at the moment
KillSwitch virus is a hazardous ransomware created by someone who was probably inspired by the methods used by WannaCry ransomware.
The authors of the ransomware named the executive file as CryptoKill.exe, probably to confuse the victims and make them search for information about CryptoKill virus online. The ransomware appears to be in development mode at the moment, meaning that the author of it is still testing and modifying this virus.
At the moment, the virus only targets %USERPROFILE%\Documents\test\ folder (to encrypt files stored on it); however, this function can be easily changed to start encrypting all system folders. The virus is set to add .switch extensions to corrupted files. Once the virus finishes the encryption task, it then launches a red message that says:
To begin with, statements provided in this message are utter nonsense and can only scare an inexperienced computer user. The described virus is a typical ransomware just like the others, just way less sophisticated.
The ransomware was developed by an amateur programmer, and while at the moment it is not distributed on a global scale, you should take all possible ransomware prevention methods because in case your computer gets hit with more advanced ransomware such as Cerber , it won't be possible to restore your files.
If your files were corrupted by an updated variant of the described malware, remove KillSwitch ransomware using or software and use data backup to restore encrypted files.

From our report of Jun 2017 · not reviewed since
Distribution of file-encrypting viruses
Ransomware viruses are mostly distributed via malicious spam, infected ad networks or RDP .
Using an up-to-date anti-malware can prevent attackers from corrupting your files; however, it is important to be aware of ransomware and its distribution methods so that you could deflect malicious attempts to infect your system. We suggest you stay away from questionable messages that fall into your Inbox or Spam folder.
Even if the email looks like its sent from a trustworthy person, do not open its attachments or links added to the message until you inspect sender's email and realize that it is a real/trustworthy one. Remember that no legitimate companies allow their employees send emails from personal emails. On top of that, avoid visiting suspicious websites, especially those that provide adult/gambling content or illegal software download links.

How to remove KillSwitch ransomware virus
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 KillSwitch ransomware virus 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 KillSwitch ransomware virus 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 KillSwitch ransomware virus, 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 KillSwitch ransomware virus 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 KillSwitch ransomware virus 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 Jun 2017 · not reviewed since
Remove KillSwitch ransomware with ease
You can easily remove KillSwitch virus with the help of anti-malware software.
However, to launch it, you will need to run your computer in Safe Mode with Networking. We have provided an easy-to-follow removal tutorial for those who have never tried to reboot PC in the aforementioned mode or never had a confrontation with malware.
We do not recommend you to try to complete KillSwitch removal manually because ransomware is not a typical program and it can be very hard to remove all of its components at the same time.
[GI=method-1]Kill the ransomware virus using these instructions. Firstly, reboot the PC into the proper mode and then delete the virus using a powerful anti-malware tool.
Find Volume Shadow Copies
You can try to recover files using Volume Shadow Copies (in case the virus did not delete it). ShadowExplorer can find these copies and use them to restore your files.
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 .switch 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.
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 KillSwitch ransomware virus
How do I open .switch files?
You cannot open them by renaming or by choosing another program. The .switch ending shows that KillSwitch ransomware virus encrypted the content, and only the matching key can reverse it. Renaming a file back to .docx or .jpg changes nothing except the icon, and it can confuse a future decryptor, so leave the names as they are.
To get the content back, use a backup, an unencrypted copy elsewhere, or a decryptor listed on No More Ransom if one exists for KillSwitch ransomware virus. Store the encrypted files on an external disk until then.
Is there a free KillSwitch ransomware virus decryptor?
We last checked on 6 October 2026, and for KillSwitch ransomware virus 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 "KillSwitch ransomware virus 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 KillSwitch ransomware virus steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by KillSwitch ransomware virus, but the only confirmed sign is files that end in .switch 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.
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.
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.
How did KillSwitch ransomware virus get on my computer?
The way KillSwitch ransomware virus 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 .switch 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.
Is KillSwitch ransomware virus 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.
Can I just remove .switch from the file names?
You can try it on a copy, but for real ransomware it will not help. The .switch extension is only a label; the file content has been scrambled with a key the attackers hold.
If a renamed copy opens normally, the malware only renamed files, which happens with some fake ransomware, and you can rename the rest back. If it does not open, leave the files as they are. Renaming encrypted files can confuse a decryptor later, so always work on copies.
My files got .switch 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 .switch 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 KillSwitch ransomware virus?
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 KillSwitch ransomware virus, 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 6, 2026)
- No More Ransom (read October 6, 2026)
- FTC: How to recognize, remove and avoid malware (read October 6, 2026)
- Microsoft Learn: Microsoft Defender Offline (read October 6, 2026)
- Microsoft Learn: How Microsoft names malware (read October 6, 2026)