What is osa9.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 osa9.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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Osa9.exe file information

Windows Task Manager with osa9
Osa9.exe process in Windows Task Manager

The process known as Microsoft Office (version 2000 component) belongs to software Microsoft Office (version 2000, 2000 SR-1, 2000 Premium, 2000 Professional, 2000 SR-1 Premium) or Microsoft Word (version 2000 SR-1) or Microsoft Office Standard or Microsoft Excel (version 2000 SR-1) or Microsoft FrontPage (version 2000) or Microsoft Office Ultimate (version 2007) or Microsoft Office Access Setup by Microsoft (

Description: Osa9.exe is not essential for the Windows OS and causes relatively few problems. Osa9.exe is located in a subfolder of "C:\Program Files"—e.g. C:\Program Files\Microsoft Office\Office\. Known file sizes on Windows 10/8/7/XP are 65,588 bytes (96% of all occurrences) or 143,412 bytes. 
The program has a visible window. The application is loaded during the Windows boot process (see Registry key: MACHINE\User Shell Folders, MACHINE\Run). It is not a Windows system file. You can uninstall this program in the Control Panel. Therefore the technical security rating is 7% dangerous; however you should also read the user reviews.

Uninstalling this variant: You can uninstall Microsoft Office 2000 Premium or Microsoft Office 2000 SR-1, or ask Support team for help. Go to Microsoft Office 2000 Premium or Microsoft Office 2000 SR-1 in the Windows Control Panel (Software or Programs section) to uninstall it, or go to for Customer Support.

Recommended: Identify osa9.exe related errors

If osa9.exe is located in the C:\Windows\System32 folder, the security rating is 65% dangerous. The file size is 47,351 bytes (66% of all occurrences) or 48,887 bytes. There is no file information. The application is loaded during the Windows boot process (see Registry key: MACHINE\User Shell Folders, MACHINE\Run). The file is not a Windows system file. The program is not visible. Osa9.exe is an unknown file in the Windows folder.

External information from Paul Collins:

Important: Some malware camouflages itself as osa9.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder, for example TROJ_DLOADER.QMP or TROJ_DLOADER.QPS (detected by TrendMicro), and Backdoor.Win32.Agent.aou (detected by Kaspersky). Therefore, you should check the osa9.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

Initializes some of the common fonts installed by Office 2000 among other things. Can be safly removed, but will effect preformance.
  Torey   (further information)
The OSA9.exe file initializes the shared code that is used by the Office 2000 programs. The benefit of using the OSA9.exe file to initialize shared code is that the Office 2000 programs start faster. If the Office 2000 programs initialize shared code (instead of OSA9.exe), the time it takes for the program to start increases.
Osa9.exe is part of Microsoft Office 2007, and is automatically started at logon. Sometimes it crashes shortly thereafter. It may cause open windows to lose focus repeatedly shortly after logon (annoying but not dangerous).
osa9.exe takes alot of CPU speed, thus slowing the computer.
  Jabez Gitonga (Kenya)  
From M$FT site
  RAJ   (further information)
It eats the CPU alive!!!!

Rating chart

Summary: Average user rating of osa9.exe: based on 6 votes with 6 user comments. 3 users think osa9.exe is essential for Windows or an installed application. One user thinks it's probably harmless. One user thinks it's neither essential nor dangerous. One user thinks osa9.exe is dangerous and recommends removing it. One user is not sure about it.

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Best practices for resolving osa9 issues

A clean and tidy computer is the key requirement for avoiding problems with osa9. 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 osa9.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

osa9.exe [all]