Ransom:MSIL/FileCryptor.A!MTB is a detection by Microsoft Defender Antivirus for a hazardous computer threat that is technically dubbed as Ransomware, File-Coder, or Crypto-virus. Ransom:MSIL/FileCryptor.A!MTB can take away the control of computer users to their files because the virus will apply a complex method to lock it. Obviously, makers of Ransom:MSIL/FileCryptor.A!MTB now dominates the affected data and user have no access to it. For this reason, some victims were forced to pay the ransom money that attacker’s are demanding before they can hand overt the required recovery tool to the victims.

Threat Behavior

Ransom:MSIL/FileCryptor.A!MTB spreads in the same manner as common computer viruses. It takes advantages of the inter-connected computers globally for the widespread deployment campaign. Among the favorite of attackers is the utilization of phishing emails where they will attach the virus and influence the recipients to open the file through attractive subject and message.

Other than email, Ransom:MSIL/FileCryptor.A!MTB also spreads via the social engineering attack where the virus or malicious link is sent to the contact list of a hacked accounts. Trojan downloader, RDP exploitation, cracked applications, and web injectors or infected websites also helps in the massive distribution of Ransom:MSIL/FileCryptor.A!MTB.


Once Ransom:MSIL/FileCryptor.A!MTB is executed on the computer, it drops several files on System folder. If boot sequence is required by the virus, it adds a Windows registry entry that initializes the virus code on every start-up of the operating system.

When Ransom:MSIL/FileCryptor.A!MTB is active, it establishes a connection to remote server and obtain necessary commands and public key and proceeds with file encryption procedures. The intention is to block user’s access to the files so that attacker’s can force the victims to pay for the recovery software.

List of Variants

List of Ransom:MSIL/FileCryptor.A!MTB Variants
Version NameAlert LevelDate Added
Ransom:MSIL/FileCryptor.AA!MTBSevereDec 23, 2019
Ransom:MSIL/FileCryptor.A!rfnSevereMar 18, 2020
Ransom:MSIL/FileCryptor.E!MTBSevereApr 08, 2020
Ransom:MSIL/FileCryptor.DSA!MTBSevereAug 04, 2020
Ransom:MSIL/FileCryptor.T!MTBSevereNov 02, 2020
Ransom:MSIL/FileCryptor.S!MTBSevereNov 04, 2020
Ransom:MSIL/FileCryptor.AZ!MTBSevereNov 06, 2020
Ransom:Win32/FileCryptor.PC!MTBSevereNov 19, 2020
Ransom:MSIL/FileCryptor.AE!MTBSevereNov 20, 2020
For complete details including full list of Ransom:Win32/FileCryptor variants, please refer to this Microsoft Security Intelligence page

How to remove Ransom:MSIL/FileCryptor.A!MTB?

To totally remove Ransom:MSIL/FileCryptor.A!MTB from the computer and get rid of relevant virus and trojan, please execute the procedures as stated on this page. Make sure that you have completely scan the system with suggested malware removal tools and virus scanners.

Remove Ransom:MSIL/FileCryptor.A!MTB Instantly

To instantly remove Ransom:MSIL/FileCryptor.A!MTB, we suggest that you scan the infected computer with this powerful anti-malware tool. It can detect and get rid of Trojans, viruses, malware, and adware from the infected computer. To fully protect the computer against Ransom:MSIL/FileCryptor.A!MTB or similar attack, you can activate Malwarebytes to have real-time scanning and complete defense against all forms of threats.

1. Download Malwarebytes Anti-Malware from the link below. Save the file on your hard drive.

2. Once the download completes, double-click on the file MBSetup.exe to run the program.

3. Select desired installation package whether for Personal Computer or Work Computer.

4. On next window, click Install button to proceed.

MBAM Default Install

5. Just proceed with the succeeding prompts until it start to execute the installation procedure.

6. Installation process will take less than a minute. It should run automatically after completing the setup.

7. When Malwarebytes Anti-Malware interface appears, please select Scan on the menu. The program will check for any available update before proceeding. Do not skip this step. Virus scan may take a while, please wait for the process to finish.


8. When scanning is done, Malwarebytes Anti-Malware will display the list of identified threats. Remove all and restart the computer to finalized the scan process.

After executing the above instructions, Ransom:MSIL/FileCryptor.A!MTB should have been eliminated totally from the computer. If there are still signs of infection or computer is displaying unusual behaviors, please continue with the remaining procedures.

Stage 1 : Start Windows in Safe Mode With Networking

Windows 10 Guide

1. Click on Windows logo and select Power icon when options pop-ups.
2. Select Restart from the options while pressing Shift key on the keyboard.
3. Choose an Option window will appear, select the Troubleshoot button.
4. On next window, please choose Advanced Option.
5. On Advanced Option window, click on Startup Settings and then, click Restart button to reboot the computer.
6. When Windows boot on Startup Settings, press function key F5 or number 5 on keyboard.

A simpler alternative for Windows 10 users is to scan the computer with Microsoft Defender Offline. This will run a virus scan in the recovery environment.

Windows 8 Guide

1. Click Windows Start icon at the lower left section of the screen.
2. Open Search window and type Advanced in the field. It will open General PC Settings.
3. Click on Advanced Startup and then, click on Restart Now button.
4. Once the computer starts in Advanced Startup option menu, select Troubleshoot.
5. Next, click on Advanced Options to reveal the next section.
6. Click Startup settings and then, click Restart button to boot the PC in Startup Settings.
7. Use function key F5 or number key 5 to Enable Safe Mode with Networking.

Stage 2 :Double Check with Microsoft Security Apps

Microsoft Windows has built-in security application that you can use to double-check if computer is still infected with Ransom:MSIL/FileCryptor.A!MTB. For Windows 8 and 10 users, please run Windows Defender. Users of Windows Vista and older versions can utilize Microsoft Security Essentials to remove Ransom:MSIL/FileCryptor.A!MTB virus.

Windows 8 / 10 Instructions:

Windows Defender is a free tool that was built help you remove Ransom:MSIL/FileCryptor.A!MTB, viruses, and other malicious items from Windows 8 or Windows 10 system. Follow these procedures to scan your computer with Windows Defender:

1. Tap or click the Search charm, search for defender, and then open Windows Defender.

If Windows Defender is not yet installed on the computer, please proceed to download page using the link below. It also contains detailed instruction to install and use the program effectively. Proper usage is required to totally remove Ransom:MSIL/FileCryptor.A!MTB


2. On the Home tab, click Full under Scan Options. Click Scan now to start scanning for presence of Ransom:MSIL/FileCryptor.A!MTB. The process may take a while to complete.


3. After the scan, delete/quarantine identified threats wether it is relevant to Ransom:MSIL/FileCryptor.A!MTB or not. You may now restart Windows to complete the virus removal process.

Windows XP, Windows Vista, and Windows 7 Instructions:

1. Open Microsoft Security Essentials by going to Windows Start > All Programs. If the tool is not yet installed on the computer, please download Microsoft Security Essentials from the link below. Save the file on your hard drive.

Complete installation guide and usage are also provided on the same link. It is essential in removing Ransom:MSIL/FileCryptor.A!MTB effectively. If Microsoft Security Essentials is already installed on the PC, please proceed with the steps below.

2. On Microsoft Security Essentials Home screen, please choose Full under Scan Options.

MSE Full Scan

3. Click on Scan Now button to start detecting Ransom:MSIL/FileCryptor.A!MTB items, viruses, and malware on the PC. Scan may take a while, please be patient and wait for the process to end.

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