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 runonce.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.
Description: Runonce.exe is an important part of Windows, but often causes problems. The file runonce.exe is located in a subfolder of C:\Windows.
Known file sizes on Windows 8/7/XP are 50,688 bytes (33% of all occurrences), 34,816 bytes, 33,792 bytes or 36,864 bytes.
The runonce.exe file is a Windows system file. The file is a Microsoft signed file. The program is not visible. Therefore the technical security rating is 1% dangerous; however you should also read the user reviews.
Recommended: Identify runonce.exe related errors
If runonce.exe is located in the C:\Windows\System32 folder, the security rating is 2% dangerous. The file size is 50,688 bytes (60% of all occurrences), 38,400 bytes or 14,336 bytes. The runonce.exe file is a Windows system file. Runonce.exe is a trustworthy file from Microsoft. The program is not visible.
External information from Paul Collins:
There are different files with the same name:
Important: Some malware camouflages itself as runonce.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the runonce.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.
A clean and tidy computer is the key requirement for avoiding problems with runonce. 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 doing a repair of your installation, or in the case of Windows 8, 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 runonce.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.