What is OAcat.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 OAcat.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.

Click to Run a Free Scan for OAcat.exe related errors

OAcat.exe file information

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

The process known as Online Armor Component or Online Armor Service Starter belongs to software Emsisoft Online Armor or Online Armor or Online Armor Firewall by Emsisoft GmbH or Emsi Software GmbH ( or Tall Emu (

Description: OAcat.exe is not essential for the Windows OS and causes relatively few problems. The file OAcat.exe is located in a subfolder of "C:\Program Files". Known file sizes on Windows 10/8/7/XP are 584,864 bytes (25% of all occurrences), 216,072 bytes and 9 more variants. 
The program is not visible. The file has a digital signature. The file is not a Windows core file. It can change the behavior of other programs or manipulate other programs. OAcat.exe is able to monitor applications, manipulate other programs and record keyboard and mouse inputs. Therefore the technical security rating is 48% dangerous, however you should also read the user reviews.

Uninstalling this variant: It is possible to turn to the software developer, Emsisoft, for advice, update to a possibly corrected version or remove the entire program Online Armor using Windows Control Panel.

Recommended: Identify OAcat.exe related errors

Important: Some malware camouflages itself as OAcat.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the OAcat.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

without oacat.exe Online Armor firewall canĀ“t be run
  meetoo   (further information)
part of well-known and very popular firewall Online Armor
  meetoo   (further information)

Summary: Average user rating of OAcat.exe: based on 2 votes with 2 user comments. 2 users think OAcat.exe is essential for Windows or an installed application.

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Best practices for resolving OAcat issues

A clean and tidy computer is the key requirement for avoiding problems with OAcat. 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 OAcat.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

OAcat.exe [all]