Most antivirus programs identify SfX.DlL as malware—e.g. TrendMicro identifies it as TROJ_KOOBFACE.GM or TROJ_TINXYPROX.B, and Kaspersky identifies it as Net-Worm.Win32.Koobface.bhd or Trojan-Downloader.Win32.Agent.cotp.
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Description: SfX.DlL is not essential for Windows and will often cause problems. The file SfX.DlL is located in a subfolder of "C:\Program Files".
Known file sizes on Windows 10/8/7/XP are 33,792 bytes (72% of all occurrences), 10,752 bytes or 11,264 bytes.
The service can be started or stopped from Services in the Control Panel or by other programs. The program has no file description. The program is not visible. There is no detailed description of this service. The file is not a Windows core file. SfX.DlL appears to be a compressed file. Therefore the technical security rating is 56% dangerous.
Recommended: Identify SfX.DlL related errors
Important: You should check the SfX.DlL 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.
The following programs have also been shown useful for a deeper analysis: ASecurity Task Manager examines the active SfX process on your computer and clearly tells you what it is doing. Malwarebytes' well-known Banti-malware tool tells you if the SfX.DlL on your computer displays annoying ads, slowing it down. This type of unwanted adware program is not considered by some antivirus software to be a virus and is therefore not marked for cleanup.
A clean and tidy computer is the key requirement for avoiding PC trouble. This means running a scan for malware, cleaning your hard drive using 1cleanmgr and 2sfc /scannow, 3uninstalling programs that you no longer need, checking for Autostart programs (using 4msconfig) and enabling Windows' 5Automatic Update. Always remember to perform periodic backups, or at least to set restore points.