What is DfSdkS64.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 DfSdkS64.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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DfSdkS64.exe file information

Windows Task Manager with DfSdkS64
DfSdkS64.exe process in Windows Task Manager

The process known as mst Defrag SDK Service belongs to software Ashampoo WinOptimizer (version 11 v., 10 v., 2013 v.) or Ashampoo HDD Control (version 2 v.) by mst software GmbH, Germany (

Description: DfSdkS64.exe is not essential for Windows and will often cause problems. DfSdkS64.exe is located in a subfolder of "C:\Program Files" or sometimes in a subfolder of the user's profile folder or in a subfolder of C:\. The file size on Windows 10/8/7/XP is 544,768 bytes. 
The program is not visible. The file is not a Windows core file. DfSdkS64.exe is able to connect to the Internet and monitor applications. Therefore the technical security rating is 40% dangerous, however you should also read the user reviews.

Uninstalling this variant: In case you experience problems using DfSdkS64.exe, you may also do the following:

Recommended: Identify DfSdkS64.exe related errors

Important: Some malware camouflages itself as DfSdkS64.exe. Therefore, you should check the DfSdkS64.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

mst Defrag SDK Service ist Teil der Software Ashampoo WinOptimizer (Version 2012 v.) bzw. Ashampoo HDD Control (Version 2). Der Hersteller dieses Software-Produktes ist mst software GmbH, Germany (
  kATZE   (further information)
hat sich nach einer Optimierung mit Ashampoo11 selbständig aktiviert. Mühsam.
Die Datei defragmentiert grade meine SSD.. auf Dauer schätze ich sie als extrem schädlich ein, da das wear leveling ausgehebelt wird und die SSD einer hohen Abnutzung unterliegt, was sich negativ auf die Haltbarkeit auswirkt.

Summary: Average user rating of DfSdkS64.exe: based on 2 votes with 3 user comments. 2 users suspect danger. One user is not sure about it.

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Best practices for resolving DfSdkS64 issues

A clean and tidy computer is the key requirement for avoiding problems with DfSdkS64. 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 DfSdkS64.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

DfSdkS64.exe [all]