What is TMAS_OEMon.exe?

The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the TMAS_OEMon.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.

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TMAS_OEMon.exe file information

Windows Task Manager with TMAS_OEMon
TMAS_OEMon.exe process in Windows Task Manager

The process known as Trend Micro Anti-Spam for OE monitor or Trend Micro Anti-Spam Toolbar

belongs to software Trend Micro Internet Security or Trend Micro Anti-Spam or Trend Micro Titanium Maximum Security or Trend Micro™ Titanium™ Maximum or Trend Micro Titanium Internet Security or Trend Micro Worry-Free Business Security or Trend Micro Anti-Spam for Outlook

by Trend Micro (

Description: TMAS_OEMon.exe is not essential for Windows and will often cause problems. The file TMAS_OEMon.exe is located in a subfolder of "C:\Program Files". Known file sizes on Windows 10/8/7/XP are 492,808 bytes (35% of all occurrences), 176,201 bytes and 8 more variants. 
It is not a Windows system file. The program is not visible. The process starts when Windows starts (see Registry key: Run, DEFAULT\Run, MACHINE\Run). The file has a digital signature. The file is a Verisign signed file. TMAS_OEMon.exe is able to record keyboard and mouse inputs and monitor applications. Therefore the technical security rating is 47% dangerous; however you should also read the user reviews.

Uninstalling this variant: If you are having problems with TMAS_OEMon.exe, you may also do the following:
  1) uninstall the program using the Control Panel ⇒ Uninstall a ProgramTrend Micro Internet Security or Trend Micro Titanium Maximum Security
  2) visit the vendor’s support site
  3) make sure that you have installed the latest version.

Recommended: Identify TMAS_OEMon.exe related errors

Important: Some malware camouflages itself as TMAS_OEMon.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the TMAS_OEMon.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

It messed up Outlook Express
this is associated with Trendmicro (,antivirus)-anti-spam
Is is the antispam toolbar for Outlook and Outlook Express
It is not deleted when TMAS is removed in Remove Programs
When OE7 starts and you go to the first web page OE7 will lock up. Everything else seems to work fine.
It messed with my mouse so whenever I move it, it skips frames and can freeze my computer if I move it, it is best if it is removed for me.
It's the antispam component of Trend Micro
this is associated with Trendmicro (,antivirus)-anti-spam
it locks up IE if i open up sevral tabs at once
  sjc in mtl  

Rating chart

Summary: Average user rating of TMAS_OEMon.exe: based on 11 votes with 9 user comments. 3 users think TMAS_OEMon.exe is essential for Windows or an installed application. One user thinks it's probably harmless. 4 users think it's neither essential nor dangerous. 2 users suspect danger. One user thinks TMAS_OEMon.exe is dangerous and recommends removing it. One user is not sure about it.

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Best practices for resolving TMAS_OEMon issues

A clean and tidy computer is the key requirement for avoiding problems with TMAS_OEMon. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the TMAS_OEMon.exe process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

TMAS_OEMon.exe [all]