What is InstallStub.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 InstallStub.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 InstallStub.exe related errors

InstallStub.exe file information

The process known as InstallStub or Enables Plaxo to integrate securely with Outlook Express belongs to software Plaxo InstallStub or Plaxo Integration for Outlook Express by Plaxo (

Description: InstallStub.exe is not essential for the Windows OS and causes relatively few problems. InstallStub.exe is located in a subfolder of C:\Windows—typically C:\Program Files\Plaxo\\ or C:\WINDOWS\Plaxo\\. The file size on Windows 10/8/7/XP is 116,736 bytes. 
The program is not visible. The InstallStub.exe file is an unknown file in the Windows folder. The program starts upon Windows startup (see Registry key: Run). The InstallStub.exe file is not a Windows core file. InstallStub.exe is able to monitor applications. Therefore the technical security rating is 66% dangerous, however you should also read the user reviews.

Recommended: Identify InstallStub.exe related errors

If InstallStub.exe is located in a subfolder of "C:\Program Files", the security rating is 63% dangerous. The file size is 116,736 bytes (66% of all occurrences) or 178,248 bytes. The program has no visible window. InstallStub.exe is not a Windows core file. The application is loaded during the Windows boot process (see Registry key: Run). It can change the behavior of other programs or manipulate other programs. InstallStub.exe is able to monitor applications.

Uninstalling this variant: You could uninstall the program using the Control Panel ⇒ Uninstall a ProgramPlaxo.

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

InstallStub.exe 02/06/03 62K Plaxo enables you to automatically update your address book
Plaxo service used to update address book + sync work and home calendars
  Steve Harris   (further information)
InstallStub.exe is a subscription based outlook & outlook express organizer / updater
  Rick   (further information)
Plaxo service for address book updates
It slows your computer down
  Menno van de Veen  
Installstub.exe is used to attach Plaxo to Outlook Express when it starts up, since Outlook Express has no API.
  Stacy Martin - Plaxo Privacy Officer   (further information)
Just updated your email contacts
  Tim C  
IT collects email addresses, how can that be safe?
Plaxo file that can get infected; causes pop-ups
Updater module of Plaxo, but it WAS NOT UNINSTALLED when I uninstalled Plaxo and it still demands internet access. Spyware-like practice.
never had a problem with it or my computer since installing it leaving me to believe that it is in fact not dangerous
Used for updating the address book in Plaxo. Phising is possible with this.
  Krish N.  

Rating chart

Summary: Average user rating of InstallStub.exe: based on 21 votes with 12 user comments. 14 users think InstallStub.exe is essential for Windows or an installed application. One user thinks it's probably harmless. 2 users think it's neither essential nor dangerous. 2 users suspect danger. 2 users think InstallStub.exe is dangerous and recommend removing it.

Do you have additional information?
What do you know about InstallStub.exe:
How would you rate it:
Link for more info:
Your Name:

Best practices for resolving InstallStub issues

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

InstallStub.exe [all]