What is Fast.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 Fast.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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Fast.exe file information

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

The process known as Super Fast User Switcher belongs to software Microsoft Windows Operating System or Powertoys For Windows XP by Microsoft (

Description: Fast.exe is not essential for the Windows OS and causes relatively few problems. The file Fast.exe is located in the C:\Windows\System32 folder. The file size on Windows 10/8/7/XP is 49,216 bytes. 
Fast.exe is certified by a trustworthy company. It is not a Windows core file. The program has no visible window. The process can be uninstalled in the Control Panel. Therefore the technical security rating is 30% dangerous, however you should also read the user reviews.

Uninstalling this variant: You can uninstall the program Powertoys For Windows XP, update it, or ask Customer Support for help. Go to to update it, go to for support, or go to Powertoys For Windows XP in Windows Control Panel (Software or Programs section) to uninstall it.

Recommended: Identify Fast.exe related errors

External information from Paul Collins:
There are different files with the same name:

Important: Some malware disguises itself as Fast.exe, particularly when not located in the C:\Windows\System32 folder. Therefore, you should check the Fast.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

fast.exe is a part of the Windows XP PowerToys. It gives users the possibility for a user to switch from one user account to another with a single click. This program is a non-essential system process, and is installed for ease of use.
  Frits boelema  
not done no damage as yet. computer still runs at optimum,,, happy dayz

Rating chart

Summary: Average user rating of Fast.exe: based on 6 votes with 2 user comments. 3 users think Fast.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.

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Best practices for resolving Fast issues

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

Fast.exe [all]